I don't know much about youth culture in China, maybe all their teens are well behaved and obedient... But my working experience is largely with "transition" s

I don't know much about youth culture in China, maybe all their teens are well behaved and obedient... But my working experience is largely with "transition" students in America and can tell you that rules like this are like commanding the tide not to go out. At best you teach them that your rules are arbitrary and give them a framework for subverting them, they may just reject your authority outright and then you've got nothing...