diff --git a/src/actions/sessions.ts b/src/actions/sessions.ts
index 33b5fcee..a43f7aca 100644
--- a/src/actions/sessions.ts
+++ b/src/actions/sessions.ts
@@ -9,7 +9,8 @@ import { logger } from "@/lib/logger";
 
 /**
  * Invalidate every CMS JWT for the signed-in user by bumping website_jwt_version,
- * revoke personal access tokens, then end the current browser session too.
+ * revoke personal access tokens, revoke the game SSO ticket, then end the
+ * current browser session too.
  */
 export async function signOutEverywhere(): Promise<void> {
 	const session = await auth();
@@ -24,6 +25,7 @@ export async function signOutEverywhere(): Promise<void> {
 			.update(User)
 			.set({
 				websiteJwtVersion: sql`${User.websiteJwtVersion} + 1`,
+				authTicket: "",
 			})
 			.where(eq(User.id, userId));
 		await invalidateJwtVersionCache(userId);
@@ -57,3 +59,26 @@ export async function signOutEverywhere(): Promise<void> {
 
 	await signOut({ redirectTo: "/login?signedOutAll=1" });
 }
+
+/**
+ * Log the current user out of the website AND revoke their game SSO ticket.
+ *
+ * Without revoking it, a ticket leaked via logs/history/referrers stays valid
+ * for the emulator after logout. Clearing the ticket makes any future client
+ * connection with it invalid.
+ */
+export async function signOutAndRevokeTicket(): Promise<void> {
+	const session = await auth();
+	const userId = Number(session?.user?.id);
+	if (Number.isInteger(userId) && userId > 0) {
+		try {
+			await db.update(User).set({ authTicket: "" }).where(eq(User.id, userId));
+		} catch (err) {
+			logger.warn("Failed to revoke SSO ticket during sign out", {
+				userId,
+				error: err instanceof Error ? err.message : "Unknown",
+			});
+		}
+	}
+	await signOut({ redirectTo: "/" });
+}
diff --git a/src/app/client/client-view.tsx b/src/app/client/client-view.tsx
index 99cd0453..d84ffa09 100644
--- a/src/app/client/client-view.tsx
+++ b/src/app/client/client-view.tsx
@@ -1,7 +1,6 @@
 "use client";
 
 import { LogOut } from "lucide-react";
-import { signOut } from "next-auth/react";
 import {
 	type ReactNode,
 	useCallback,
@@ -10,7 +9,9 @@ import {
 	useRef,
 	useState,
 } from "react";
+import { signOutAndRevokeTicket } from "@/actions/sessions";
 import Link from "@/components/link";
+import { buildClientLoginUrl } from "@/lib/client-url";
 
 function ToolbarBtn({
 	onClick,
@@ -94,9 +95,7 @@ export function ClientView({
 		return () => document.removeEventListener("fullscreenchange", onChange);
 	}, []);
 
-	const base = clientUrl.replace(/(\?|&)sso=[^&]*/, "");
-	const sep = base.includes("?") ? "&" : "?";
-	const clientSrc = `${base}${sep}sso=${encodeURIComponent(ticket)}`;
+	const clientSrc = buildClientLoginUrl(clientUrl, ticket);
 
 	const toolbarRef = useRef<HTMLDivElement>(null);
 	const dragRef = useRef({ startX: 0, startY: 0, startTop: 0, startLeft: 0 });
@@ -361,7 +360,7 @@ export function ClientView({
 							</svg>
 						</div>
 						<ToolbarBtn
-							onClick={() => signOut({ callbackUrl: "/" })}
+							onClick={() => void signOutAndRevokeTicket()}
 							title="Logout"
 						>
 							<LogOut size={14} />
@@ -382,6 +381,7 @@ export function ClientView({
 					}`}
 					title={hotelName}
 					allow="autoplay; gamepad; fullscreen"
+					referrerPolicy="no-referrer"
 					loading="eager"
 				/>
 			</div>
diff --git a/src/components/top-header.tsx b/src/components/top-header.tsx
index 6fb3ceb9..240014af 100644
--- a/src/components/top-header.tsx
+++ b/src/components/top-header.tsx
@@ -2,11 +2,11 @@ import { count, eq, inArray } from "drizzle-orm";
 import Image from "next/image";
 import type { Session } from "next-auth";
 import { getTranslations } from "next-intl/server";
+import { signOutAndRevokeTicket } from "@/actions/sessions";
 import { HeaderUserIdentity } from "@/components/header-user-identity";
 import Link from "@/components/link";
 import { RoomQuickEntry } from "@/components/room-quick-entry";
 import { UserAvatarThumbnail } from "@/components/shared/user-avatar-thumbnail";
-import { signOut } from "@/lib/auth";
 import { cached } from "@/lib/cache";
 import {
 	db,
@@ -405,12 +405,7 @@ export async function TopHeader({ session }: { session: Session | null }) {
 										"color-mix(in srgb, var(--color-text-muted) 12%, transparent)",
 								}}
 							/>
-							<form
-								action={async () => {
-									"use server";
-									await signOut({ redirectTo: "/" });
-								}}
-							>
+							<form action={signOutAndRevokeTicket}>
 								<button
 									type="submit"
 									role="menuitem"
diff --git a/src/lib/auth/sso-ticket.test.ts b/src/lib/auth/sso-ticket.test.ts
index 33fd60c4..a4e34af0 100644
--- a/src/lib/auth/sso-ticket.test.ts
+++ b/src/lib/auth/sso-ticket.test.ts
@@ -1,15 +1,31 @@
 import { beforeEach, describe, expect, it, vi } from "vitest";
-import { generateSsoTicket } from "./sso-ticket";
+import { generateSsoTicket, isValidTicketShape } from "./sso-ticket";
 
 const UUID_RE =
 	/^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/;
 
+const VALID_UUID = "12345678-1234-4123-8123-123456789abc";
+
+const readState = vi.hoisted(() => ({ authTicket: "" }));
+
+const mockLimit = vi.hoisted(() => ({
+	limit: () => Promise.resolve([{ authTicket: readState.authTicket }]),
+}));
 const mockWhere = vi.hoisted(() => vi.fn().mockResolvedValue(undefined));
-const mockSet = vi.hoisted(() => vi.fn(() => ({ where: mockWhere })));
+const mockSet = vi.hoisted(() =>
+	vi.fn((values: { authTicket?: string; ipCurrent?: string }) => {
+		if (values.authTicket !== undefined)
+			readState.authTicket = values.authTicket;
+		return { where: mockWhere };
+	}),
+);
 const mockUpdate = vi.hoisted(() => vi.fn(() => ({ set: mockSet })));
+const mockSelect = vi.hoisted(() =>
+	vi.fn(() => ({ from: () => ({ where: () => mockLimit }) })),
+);
 
 vi.mock("@/lib/db", () => ({
-	db: { update: mockUpdate },
+	db: { select: mockSelect, update: mockUpdate },
 	User: { id: "id" },
 }));
 
@@ -20,10 +36,10 @@ describe("generateSsoTicket", () => {
 		expect(UUID_RE.test(t.slice("AtomHotel-".length))).toBe(true);
 	});
 
-	it("strips every space in the hotel name", () => {
-		expect(generateSsoTicket("My Cool Hotel").startsWith("MyCoolHotel-")).toBe(
-			true,
-		);
+	it("strips every whitespace char in the hotel name", () => {
+		expect(
+			generateSsoTicket("My\tCool\nHotel").startsWith("MyCoolHotel-"),
+		).toBe(true);
 	});
 
 	it("produces a fresh ticket each call", () => {
@@ -31,19 +47,43 @@ describe("generateSsoTicket", () => {
 	});
 });
 
+describe("isValidTicketShape", () => {
+	it("accepts a matching hotel-prefixed UUID", () => {
+		expect(isValidTicketShape("Atom Hotel", `AtomHotel-${VALID_UUID}`)).toBe(
+			true,
+		);
+	});
+
+	it("rejects a ticket with a different hotel prefix", () => {
+		expect(isValidTicketShape("Atom", `Other-${VALID_UUID}`)).toBe(false);
+	});
+
+	it("rejects junk", () => {
+		expect(isValidTicketShape("Atom", "")).toBe(false);
+		expect(isValidTicketShape("Atom", "Atom-not-a-uuid")).toBe(false);
+		expect(isValidTicketShape("Atom", "Atom-")).toBe(false);
+	});
+});
+
 describe("issueSsoTicket", () => {
 	beforeEach(() => {
 		vi.clearAllMocks();
-		mockSet.mockReturnValue({ where: mockWhere });
-		mockUpdate.mockReturnValue({ set: mockSet });
+		readState.authTicket = "";
+		mockSet.mockImplementation(
+			(values: { authTicket?: string; ipCurrent?: string }) => {
+				if (values.authTicket !== undefined)
+					readState.authTicket = values.authTicket;
+				return { where: mockWhere };
+			},
+		);
 		mockWhere.mockResolvedValue(undefined);
 	});
 
-	it("writes auth_ticket AND ip_current and returns the ticket", async () => {
+	it("mints a ticket and writes auth_ticket + ip_current", async () => {
 		const { issueSsoTicket } = await import("./sso-ticket");
 		const ticket = await issueSsoTicket(42, "Atom Hotel", "1.2.3.4");
-
 		expect(ticket.startsWith("AtomHotel-")).toBe(true);
+		expect(UUID_RE.test(ticket.slice("AtomHotel-".length))).toBe(true);
 		expect(mockUpdate).toHaveBeenCalled();
 		expect(mockSet).toHaveBeenCalledWith({
 			authTicket: ticket,
@@ -51,4 +91,34 @@ describe("issueSsoTicket", () => {
 		});
 		expect(mockWhere).toHaveBeenCalled();
 	});
+
+	it("reuses the outstanding ticket on the next call", async () => {
+		const { issueSsoTicket } = await import("./sso-ticket");
+		const first = await issueSsoTicket(42, "Atom Hotel", "1.1.1.1");
+		vi.clearAllMocks();
+
+		const second = await issueSsoTicket(42, "Atom Hotel", "2.2.2.2");
+		expect(second).toBe(first);
+	});
+
+	it("only refreshes the IP when reusing", async () => {
+		const { issueSsoTicket } = await import("./sso-ticket");
+		await issueSsoTicket(42, "Atom Hotel", "1.1.1.1");
+		vi.clearAllMocks();
+
+		await issueSsoTicket(42, "Atom Hotel", "2.2.2.2");
+		expect(mockSet).toHaveBeenCalledWith({ ipCurrent: "2.2.2.2" });
+		expect(mockSet).not.toHaveBeenCalledWith(
+			expect.objectContaining({ authTicket: expect.any(String) }),
+		);
+	});
+
+	it("rotates a stale ticket whose prefix no longer matches the hotel", async () => {
+		const { issueSsoTicket } = await import("./sso-ticket");
+		readState.authTicket = `OtherHotel-${VALID_UUID}`;
+
+		const ticket = await issueSsoTicket(42, "Atom Hotel", "1.1.1.1");
+		expect(ticket.startsWith("AtomHotel-")).toBe(true);
+		expect(readState.authTicket).toBe(ticket);
+	});
 });
diff --git a/src/lib/auth/sso-ticket.ts b/src/lib/auth/sso-ticket.ts
index e86730bf..b77cfd29 100644
--- a/src/lib/auth/sso-ticket.ts
+++ b/src/lib/auth/sso-ticket.ts
@@ -1,32 +1,76 @@
 import { randomUUID } from "node:crypto";
-import { eq } from "drizzle-orm";
+import { and, eq } from "drizzle-orm";
 import { db, User } from "@/lib/db";
 
+const UUID_RE =
+	/^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/;
+
 /**
  * Build the SSO ticket exactly like AtomCMS's User::ssoTicket():
  *   $hotelName = Str::replace(' ', '', setting('hotel_name'));
  *   sprintf('%s-%s', $hotelName, Str::uuid());
- * i.e. the hotel name with ALL spaces removed, a dash, then a v4 UUID.
+ * i.e. the hotel name with ALL whitespace removed, a dash, then a v4 UUID.
  * The emulator validates this exact value when the Nitro/Flash client connects.
  */
 export function generateSsoTicket(hotelName: string): string {
-	const normalized = hotelName.replace(/ /g, "");
+	const normalized = hotelName.replace(/[\s]+/g, "");
 	return `${normalized}-${randomUUID()}`;
 }
 
+/**
+ * True when the ticket is exactly '{hotelName-no-spaces}-{v4 UUID}', i.e. the
+ * shape the emulator accepts for this hotel. Anything else is treated as stale
+ * and replaced with a fresh ticket.
+ */
+export function isValidTicketShape(hotelName: string, ticket: string): boolean {
+	const normalized = hotelName.replace(/[\s]+/g, "");
+	return (
+		ticket.length > normalized.length + 1 &&
+		ticket.startsWith(`${normalized}-`) &&
+		UUID_RE.test(ticket.slice(normalized.length + 1))
+	);
+}
+
+async function readTicket(userId: number): Promise<string | null> {
+	const rows = await db
+		.select({ authTicket: User.authTicket })
+		.from(User)
+		.where(eq(User.id, userId))
+		.limit(1);
+	return rows[0]?.authTicket ?? null;
+}
+
 /**
  * Generate a ticket and persist it like AtomCMS: writes auth_ticket AND
  * ip_current on the user, then returns the ticket for the client launcher.
+ *
+ * The outstanding ticket is REUSED instead of being regenerated on every page
+ * load, so reloading /client or opening a second tab no longer invalidates a
+ * game session that is still connecting. When a new ticket is minted, the
+ * write is guarded against the previously-read value so concurrent launches
+ * all receive the same ticket rather than clobbering each other.
  */
 export async function issueSsoTicket(
 	userId: number,
 	hotelName: string,
 	ip: string,
 ): Promise<string> {
+	const current = await readTicket(userId);
+
+	if (current && isValidTicketShape(hotelName, current)) {
+		await db.update(User).set({ ipCurrent: ip }).where(eq(User.id, userId));
+		return current;
+	}
+
 	const ticket = generateSsoTicket(hotelName);
 	await db
 		.update(User)
 		.set({ authTicket: ticket, ipCurrent: ip })
-		.where(eq(User.id, userId));
+		.where(and(eq(User.id, userId), eq(User.authTicket, current ?? "")));
+
+	// Return whatever actually landed in the DB so every concurrent launcher
+	// sends the exact same ticket to the emulator.
+	const stored = await readTicket(userId);
+	if (stored && isValidTicketShape(hotelName, stored)) return stored;
 	return ticket;
 }
diff --git a/src/lib/client-url.test.ts b/src/lib/client-url.test.ts
new file mode 100644
index 00000000..ae5a4504
--- /dev/null
+++ b/src/lib/client-url.test.ts
@@ -0,0 +1,49 @@
+import { describe, expect, it } from "vitest";
+import { buildClientLoginUrl } from "./client-url";
+
+describe("buildClientLoginUrl", () => {
+	it("appends sso to a clean URL", () => {
+		expect(buildClientLoginUrl("https://game.hotel.nl", "Hotel-uuid")).toBe(
+			"https://game.hotel.nl?sso=Hotel-uuid",
+		);
+	});
+
+	it("uses & when a query string already exists", () => {
+		expect(
+			buildClientLoginUrl(
+				"https://game.hotel.nl/nitro?mode=nostrip&debug=1",
+				"Hotel-uuid",
+			),
+		).toBe("https://game.hotel.nl/nitro?mode=nostrip&debug=1&sso=Hotel-uuid");
+	});
+
+	it("replaces an existing sso param", () => {
+		expect(
+			buildClientLoginUrl("https://game.hotel.nl/nitro?sso=old&mode=1", "new"),
+		).toBe("https://game.hotel.nl/nitro?mode=1&sso=new");
+		expect(
+			buildClientLoginUrl("https://game.hotel.nl/nitro?sso=old", "new"),
+		).toBe("https://game.hotel.nl/nitro?sso=new");
+	});
+
+	it("keeps a fragment after the sso param", () => {
+		expect(
+			buildClientLoginUrl("https://game.hotel.nl/nitro#entry", "h-u"),
+		).toBe("https://game.hotel.nl/nitro?sso=h-u#entry");
+		expect(
+			buildClientLoginUrl("https://game.hotel.nl/nitro?sso=old#entry", "h-u"),
+		).toBe("https://game.hotel.nl/nitro?sso=h-u#entry");
+	});
+
+	it("leaves any existing non-sso fragment intact", () => {
+		expect(
+			buildClientLoginUrl("https://game.hotel.nl/nitro?tok=1#frag", "th"),
+		).toBe("https://game.hotel.nl/nitro?tok=1&sso=th#frag");
+	});
+
+	it("encodes the ticket value", () => {
+		expect(buildClientLoginUrl("https://game.hotel.nl/", "Ḟancy-ü")).toBe(
+			"https://game.hotel.nl/?sso=%E1%B8%9Eancy-%C3%BC",
+		);
+	});
+});
diff --git a/src/lib/client-url.ts b/src/lib/client-url.ts
new file mode 100644
index 00000000..1370514f
--- /dev/null
+++ b/src/lib/client-url.ts
@@ -0,0 +1,20 @@
+/**
+ * Build the Nitro launch URL with the SSO ticket as the final query param.
+ *
+ * Any existing `sso` param is removed first (both from the query string and
+ * from a `#fragment`), the ticket is appended as the last query param, and a
+ * `#fragment` is kept after it so the ticket always reaches the server.
+ */
+export function buildClientLoginUrl(clientUrl: string, ticket: string): string {
+	const [pathPart = "", ...fragments] = clientUrl.split("#");
+	const fragment = fragments.join("#");
+
+	const path = pathPart
+		.replace(/([?&])sso=[^&#]*/gi, "$1")
+		.replace(/([?&])&+/g, "$1")
+		.replace(/[?&]$/, "");
+
+	const sep = path.includes("?") ? "&" : "?";
+	const query = `${path}${sep}sso=${encodeURIComponent(ticket)}`;
+	return fragment ? `${query}#${fragment}` : query;
+}