My 16 yo high schooler thinks removing phones from the classroom is a great idea (southern US). According to him ithe number of students who are on their phones instead of paying attention is too high, he's even fallen into that trap. His middle school tried to have kids turn in their phones before they entered the room, several just snuck them in and a few were stolen. The school eventually gave up. In HS his teachers are so overwhelmed and under staffed they don't even try to enforce rules like this.