Here's a nice news program covering a student who had her wrist broken by a school security guard who apparently didn't like the way she reacted to him ordering her to clean up a piece of cake.
I'm at a bit of a loss as to why a security guard was handing out orders like that, perhaps he wasn't well-instructed on what he was supposed to be doing other than just making sure the children learn thoroughly to never question any authority figure, but that's another matter... The video explains itself.