You're right -- this is not only a problem on Apple's side, both Apple and app developers can take measurements to prevent this from happening. On Apple's side this requires fundamental changes in their (un)subscribe mechanism, but that's not likely to happen soon. Therefor, an app developer can implement best practices to ensure this doesn't happen. For example, blocking the UI with an activity indicator until the app receives OK from the APNS when firing the unregister request.
Comments
You're right -- this is not only a problem on Apple's side, both Apple and app developers can take measurements to prevent this from happening. On Apple's side this requires fundamental changes in their (un)subscribe mechanism, but that's not likely to happen soon. Therefor, an app developer can implement best practices to ensure this doesn't happen. For example, blocking the UI with an activity indicator until the app receives OK from the APNS when firing the unregister request.