I heard of an app, that is very smiliar to your idea. I can't remember what's it called or if it's in delvopment, sorry. But it's for if your spouse is abusing you or something and it records it and calls police. You can switch apps to hide it form them. I can't remember where I read it or anything but that. I read about earlier this year Lear fear cear gear.( please ignore that) maybe it's a start.