Reading the title, it did sound extreme, but in the end, sadly, I think that the school did exactly what was necessary. Not just for the scare value of being arrested. This girl kicked her teacher and punched the assistant principle in the shins. The girl needed to be retrained and anyone who's tried to retrain a child on a rampage (or anyone, frankly) knows that they can do a lot of harm to themselves thrashing around. Police are trained to deal with it, so the surest way to avoid a lawsuit must have been to call in someone who's trained to deal with restraining people.
The girl's mother is obviously one of those truly terrible parents who always side with their children. She has no clue how to raise or love her child and needs some serious punishment herself. Sorry, talk of suing schools always gets me riled up. There are very rare cases (I stress the very) when a teacher "has it in" for a kid, but from what I've seen 99.9% of the time, the kid brings it on themselves. If you go through school slacking, causing trouble in class, getting into fights or whatnot you cannot be surprised if a teacher has very little tolerance for you misbahaving. The teacher's not "picking on you" any more than police are "picking on" the repeat violent criminal by questioning him after the liquor store gets held up. If you don't want negative attention, don't be a troublemaker, period. Yeah, I got into my share of shanannagans when I was a kid, but I was by and large well behaved, I knew that there was plenty of discipline if I wasn't. When I got caught, I was punished, I didn't like it, and I think that the worst part was knowing that I'd disapponted my parents. But because I was mostly well behaved, people tended to look at those bad things that I did as just exploring boundaries and typical youthful "boys will be boys" stuff. On the other hand, there were kids I grew up with who were seldom if ever up to any good, so when they misbehaved it was just one more example of how crappy they were.
Matak's had the right of this thread, as have others who've echoed his sentiment. Kids need discipline and love, and the two go hand in hand. You can't "reason" with a child and expect them to understand right from wrong like an adult when they haven't been taught right from wrong! And you gotta follow through on your threats. A friend of mine who's training her puppy told me something interesting that I'd never thought of, and I think it applies to children as well, actually, I think that rearing children and training dogs are pretty much one in the same as far as theory.
She said that you never repeat a command. You issue it and either punish or reward as fit. By repeating all you do is teach the dog that it can respond when it wants to, it made me think of those times I've seen parents yelling (or even just telling) at their kids over and over to behave. If instead they were consistent and said "stop" and punished the child if he didn't behave, then he'd learn pretty quickly that what mom and/or dad sais, goes, and right away.