I wonder if, using GPS and accelerometer, the Phone can determine it's in the hands of a driver -- and prohibit texting use.

I mean, using the GPS it can see the speed and that it's inside a vehicle. And I would think that holding the steering wheel with the other hand, rotating it to change course etc, might have some kind of signature micro-motions and interactions through GPS/accelerometer, so that it could be determined that not only the phone it's on a car, but that also the driver holds it.