text: Allowing students to use their phones during free time could allow them to contact home as well, to tell parents at an even more convenient time that, yes, they will need to be picked up, or no, that they will not need to be picked up, before the parent has left the house (or not left the house) to do one of these two, or the parents would be notified in time to bring something up to the school that the students have forgotten. On the other hand, students could use this policy against the teachers and claim that they conveniently 'forgot' to turn off their cell phones, and were 'just checking if it was important'. However, I don't think that this would be a huge problem. After a week or two, you could stop giving students the benefit of the doubt, and start enforcing the punishments.