I have, teenage girls that is, and that's where the geo tracking comes in...when you get to where your going like to spend the night or club or (gasp) the library, then you can use your phone....you can see where they are.
Not using phone while moving sucks for sure but no phone call or text message is worth my daughter's life and she'll have something to tell her therapist...kids think they are immortal and it's not trust per se, it's safety - they need to be watching for ADULTS they may be using their phone and cross that center line and react defensively as well.
I would still use it now if I paid for my 22 y/o dtr's phone. She has had one fender-bender so far due to texting, she still denies but phone records prove otherwise...
OPMG