I remember during my student teaching I was actually very lenient with letting students have their cell phones out, and let them check them occasionally.
My line in the sand was games and selfies though. If you did that I took your phone.
The wailing and gnashing of teeth every time I took a phone away. You would have thought I was some horrible villain for taking away a cell phone when school policy states NO cell phones at all. One kid went to far as the claim that I was violating his civil rights (he was 100% serious).
