Uniforms do dick all other than look stupid. Putting everyone in the same outfit won't change a single thing about their behaviour.
The real problem lies on the parents and their unwillingness to do anything about their kids' actions. Half the time when a kid gets in trouble at school for something serious like fighting or vandalism, the parents bitch out the school for making stuff up about their kid and what an angel he/she is. I shit you not.
There should be a totally anonymous vigilante group that goes around and kicks the shit out of asshole kids and their parents.
