my thoughts on that are centered around school shootings because that’s the reason schools are adding fences. to address the points you mentioned though, during my senior year when we had a fully constructed fence people still skipped school all the time (same people that always were) so the fence did not help. the whole custody thing is better solved by the parent that should have custody letting the school know about the situation at which point the school will have a legal obligation to ensure the child’s safety. shootings aside, this leaves only making kids feel like prisoners for potential changes the fence could make.