My DD teaches 5th grade, every year there is at least one parent that tries to push the rules and their child need to keep their phone on and at their desk all day. The school district does not allow it - so every year someone tests the water and gets upset when the reaction is "No" and the parent can call the office and then they will decide if the parent can talk to the student. Usually the child is just caught in the middle - the phone rings in the classroom and then it gets confiscated and parent has to come to school to retrieve it. By 5th grade you would think the parents would learn, but no.
My husband has to check out his Facebook all the time so I have a game on my phone and when we turns his on then I do the same. It drives him crazy that I will play my game - but it is okay for him to do his Facebook. I told him that it is the same and I will stop when he does. It works.