I'm a current teacher, and I can confirm this is happening. Our school allows the teachers to implement the policy, but it's almost impossible to be the one teacher who doens't allow it. I've found that the kids spend more time trying to be on their phone than paying attention, then they (and parents) want to whine about grades. It's definitely ruined any passion I have, and I wish the school would take the France route to smartphones (i.e. usage banned in schools)