Don Cardi...from your article posted at the start of this thread:

"..Some students leave phones at nearby stores that charge small holding fees..."

What I will concede would be nice is that, while rightfully proceeding to implement this ban in the schools, the Mayor and Chancellor provided the means of a holding place for cellphones upon or just before entering the school. But even then, crafty students would probably find some way around it.

Apple

ps - you cannot ban pens in a school because students need them to write.