I came from a small country in Europe and schools followed a more strict policy. We were not allowed to change classrooms from 1-12 grade, the teachers switched classrooms. Because of that process, we created a bond with the classmates and kind of became like a family and protected one another. There was bullying, but it was minimal because the non-supervision time window was small during our 20 min lunch break. I promise, if the western schools follow the same policy all that pushing and shoving of kids during class transition will not happen. Just my 2 cents.