I assume the API provides notifications when the volume buttons are pressed so that an app that has music/sound can adjust it's own volume. Of course there is n

I assume the API provides notifications when the volume buttons are pressed so that an app that has music/sound can adjust it's own volume. Of course there is no way for apple to determine programatically that the app is using those notifications for some other purpose. So features like this end up being in the app, until a human spots it and rejects the app.