That makes sense to me.
My protocol could therefore give exemptions for calling 999 or 112.
As for safely parked, that is more tricky, parking sensor data? But in any case I wouldn't want to lose track of the greater good/big picture objective. Would a protocol that allowed none hands free use of the phone only when the engine is stopped and the car not moving not be a big step forward in terms of accident prevention compared to what we have now which is twits driving along at all speeds in all conditions texting each other? And if they choose to use the phone when not parked safety then they are still breaking a law. i am not saying there is a water tight solution, but one that assists people to do the right thing by reducing their options for doing bad things behind the wheel.