One thing I do want to point out is that "not allowing any apps to interfere with 911 calls" is much more complex than it sounds: 1. What about someone who has

One thing I do want to point out is that "not allowing any apps to interfere with 911 calls" is much more complex than it sounds: 1. What about someone who has a tablet (with no cellular functionality) but has a VoIP app installed? Clearly, the only way to call 911 on such a device would be for it to go through the VoIP app, so it seems like Android at the very least still needs VoIP apps to be able to handle 911 calls under certain circumstances, such as when there is no cellular functionality. 2. How about a situation where a cellular phone has no communication with any cell towers (for any network) but has a VoIP app installed and access to wifi? Unlikely, to be sure, but possible. In this case, the only way for the phone to reach 911 would, again, be through the VoIP app. If 911 access must get through no matter what, Android would have to let the call go through the app, despite that the phone has cellular functionality. Those are likely just a couple of instances and there's almost certainly others I haven't thought of.