I've long been a proponent of 'cell-free' zones such as theaters, restaurants and the like.
I was in the library the other day (I volunteer there) and had to ask someone to leave because she was talking on her cell-phone. She was getting book recomendations.
It would have been nice if the owners of such establishments had taken the initiative and instituted it on their own.
However, due to their inaction, other methods have been explored and they've placed the 'responsibility' into the hands of the juvenile.
Responsible use of these would be nice, but I ain't holding my breath.