diff --git a/js/app.js b/js/app.js
index df2a9db0..16195666 100644
--- a/js/app.js
+++ b/js/app.js
@@ -696,6 +696,7 @@ class Application {
 
       const openResult = this.zapController?.open({ requiresLogin });
       if (!openResult) {
+        event?.preventDefault?.();
         if (!requiresLogin) {
           this.pendingModalZapOpen = false;
         }
diff --git a/js/ui/components/VideoModal.js b/js/ui/components/VideoModal.js
index 9ced7731..938ed1eb 100644
--- a/js/ui/components/VideoModal.js
+++ b/js/ui/components/VideoModal.js
@@ -128,9 +128,14 @@ export class VideoModal {
     this.eventTarget.removeEventListener(type, listener, options);
   }
 
-  dispatch(type, detail) {
-    const event = new CustomEvent(type, { detail });
-    this.eventTarget.dispatchEvent(event);
+  dispatch(type, detail, options = {}) {
+    const config =
+      options && typeof options === "object" ? { ...options } : Object.create(null);
+    const event = new CustomEvent(type, {
+      detail,
+      cancelable: Boolean(config.cancelable),
+    });
+    return this.eventTarget.dispatchEvent(event);
   }
 
   getRoot() {
@@ -420,10 +425,14 @@ export class VideoModal {
         }
 
         if (this.modalZapRequiresLogin) {
-          this.dispatch("zap:open", {
-            video: this.activeVideo,
-            requiresLogin: true,
-          });
+          this.dispatch(
+            "zap:open",
+            {
+              video: this.activeVideo,
+              requiresLogin: true,
+            },
+            { cancelable: false },
+          );
           return;
         }
 
@@ -446,9 +455,17 @@ export class VideoModal {
           return;
         }
 
+        const allowed = this.dispatch(
+          "zap:open",
+          { video: this.activeVideo },
+          { cancelable: true },
+        );
+        if (allowed === false) {
+          return;
+        }
+
         this.modalZapPendingToggle = null;
         this.openZapDialog();
-        this.dispatch("zap:open", { video: this.activeVideo });
       });
     }
 
diff --git a/tests/video-modal-zap.test.mjs b/tests/video-modal-zap.test.mjs
index e259bf5c..bd21c978 100644
--- a/tests/video-modal-zap.test.mjs
+++ b/tests/video-modal-zap.test.mjs
@@ -358,6 +358,56 @@ await (async () => {
   app.destroy();
 })();
 
+await (async () => {
+  // Test: preventDefault is called when zap opening is rejected post-dispatch
+  const { app, modalStub } = await createApp({
+    splitAndZap: async () => ({ receipts: [] }),
+  });
+
+  let loginNotificationCount = 0;
+  app.zapController.notifyLoginRequired = () => {
+    loginNotificationCount += 1;
+  };
+
+  app.zapController.isUserLoggedIn = () => false;
+
+  modalStub.closeZapDialogCalls = [];
+
+  const preventCalls = [];
+  const event = {
+    detail: { requiresLogin: false },
+    preventDefault: () => {
+      preventCalls.push(true);
+    },
+  };
+
+  app.pendingModalZapOpen = true;
+
+  app.boundVideoModalZapOpenHandler(event);
+
+  assert.equal(
+    loginNotificationCount,
+    1,
+    "should notify login requirement when zap open is rejected",
+  );
+  assert.equal(
+    preventCalls.length,
+    1,
+    "should prevent default zap opening when controller rejects it",
+  );
+  assert.equal(
+    app.pendingModalZapOpen,
+    false,
+    "pending zap reopen flag should clear when rejection wasn't login-gated",
+  );
+  assert.deepEqual(modalStub.closeZapDialogCalls[0], {
+    silent: true,
+    restoreFocus: false,
+  });
+
+  app.destroy();
+})();
+
 await (async () => {
   // Test: session actors should not be treated as logged-in users for zaps
   const { app, modalStub } = await createApp({