I think that already exists–at least for driving and driving + texting [1]. I'm actually okay with it for those uses (I have a teen and 3 smaller kids).

I don't need to know where my teen is at all times but if I can reduce (a) her chances of dying and (b) my car insurance bill, sweet.

[1] http://www.wsoctv.com/news/news/local/aaa-testing-device-tra...