re: Why don't all schools prohibit cell phones in classrooms? I read an article that indicated

It's not the phone that is the problem.

My son can use his phone at school but they are taught to only use it when appropriate on downtime and breaks. If you are using it during class you lose it but teaching the kids to act right is much better than a zero tolerance policy.

They allow them for perception of safety, be it a parent needs to get in touch or there is an attack on a school, but teaching kids to be responsible is a much better reason to allow them.