Some schools actually have banned things such as biking to school, along with playing tag, balls, and even running during recess over the same safety boogieman. It's frustrating how the whole freedom vs security balance thing falls off a cliff when children's rights are discussed.
As a child, it is exactly prison, it's not 'like' prison. You are controlled in location, action, and speech. You are told when to use the restroom, when to eat. Feeling sleepy today or maybe not getting along with an obnoxious inmate? Too bad for you, you're powerless.
I personally believe most school violence is induced by the prison-like nature of schools. They are inmate riots of 1.