1) I would TELL my teen I am watching their driving behavior.
2) If they dont like it, don't drive!
3) They have NO freedom. Only privilege.
4) They would understand ALL of the rules going in and the ALL consequences of not following them.
5) If my teenager forces keys away from a driver that is drunk, and drives his/her car, REWARD TIME!
6) If my teenager is a great driver, me watching him will not matter, whether I wait a year or two or not.
7) Teens NEED parents to step up and do things like this, even though they SAY and THINK they don't want it.
What your saying is akin to letting children having a computer in their rooms and have the parents "trust" them by not watching what they are doing.
Perhaps you should survey the parents of the hundreds of kids who are killed every year from excessive speeding.
Your grandstand is admirable, but at 20, and until you have children of your own, respectfully, you have a highly slanted view of this product and/or service in my opinion.
And I am not affiliated with this company in any way.