Looking at my own phone right now, it just got a push notification that my wife has arrived at home. That could be useful if you wanted to track my wife.
> And why aren't push notifications E2EE?
That's a great question. And I hope the answer is "we're on it, they will be E2EE in the next release."
1. Generate a local key pair per app (never uploaded to Apple). 2. Each app can request their public key from iOS (or provided with (void) application:(UIApplication )application didRegisterForRemoteNotificationsWithDeviceToken:(NSData )deviceToken andPublickKey: (NSData *)publicKey;). 3. App uploads token + public key to their own server. 4. Server encrypts notification payload with the public key before sending to APNS. 5. Apple forwards encrypted payload to device. 6. Device uses the bundle name to look up the local private key and uses it to decrypt the payload.