the thing about kids that do pranks like this is that they want to get punished. it's a status issue. the more you punish them, the bigger their trophy and the more they can brag about it. getting retributive is something that's going to make you feel better about yourself, not something that's going to address the issue or otherwise correct their behaviour.

the ideal "punishment" would be for them to sit in the auditorium as student after student walks up to the microphone and verbally berates them for it, followed by loud audience applause. this would get the point across that the behaviour isn't "cool" and isn't going to help them make friends or get laid. so, ideally, this parade would include their friends, family members, people they have a crush on, etc.

....and, yes, they should get community service, too.

http://www.youtube.com/watch?v=qjMsU-coB2Q