I am coming from the opposite side. Restraining mechanisms in schools are much weaker where I live and since I happen to know a few teachers I know very well that the teenage classes often become pure chaos and hell, typically in the classes formed of teenagers with lower educational attainment.

Few misbehaving and defiant teens have immense power to impose disastrous externalities on their peers and the teachers. Too disastrous, in fact, to just let it go.