Our school teaches that bullying is wrong and has a zero tolerance. That said, the bullying must be seen by a teacher in order for something to occur and kids are sneaky. Mine are in elementary school though. I know bullying in middle school is worse.
Here is the "official" policy for the entire district:
http://thompson.k12.co.us/About_Us/BOE/db/j/JICDE.pdf
I am actually going into the school once it starts to talk with them about some issues my son brought up after school was already out. Things that a now retired teacher was privy to and did nothing. I do not want it to re-occur.