Earlier quoted context omitted.
I think that is a step too far. Imagine they banned books during breaks. That's how far this is. I get you want to not have them use them during class but that is the general policing class behavior that teachers are supposed to do. Why ban them during breaks when it doesn't hurt their studies?
It may not hurt their studies, but perhaps their social skills. I recently stayed at a hostel, and when I first walked in I noticed how in the common area almost every single person was alone on their phone. It made me long for the pre-smartphone days in which I imagine travelers were forced to socialize with each other. While school lunch is a slightly different situation, I think it still applies that without phone…
I'm generally all for the ban, though. I think the bads of the phone outweigh the goods in a school setting.