There wouldn't be something called ADD if the kids knew that they'd get their *** kicked if they do something stupid. I don't know how bad you guys have it there, but I've met several kids who claim they have ADD, which conveniently and magically disappears when they're told to cut the crap or they'll be sorry.
back on topic (more, somewhat)
While it doesn't seem like many people oppose corporal punishment, I must question your motives; are you guys all just agreeing with it because you can't do anything about bullying yourselves?
I'm especially surprised that the OP is referring to Australia; for as long as I've been in school there's been no bullying serious enough to warrant any concern... heck half the bullying doesn't go on record, it's no wonder they don't do anything about it.
Corporal punishment may be a good way to teach kids what's acceptable and what's not (heck, if you're getting beaten up for it, you must be screwing something up) but it shouldn't be a means to stop bullying or something that you feel you're powerless against. Bullying will persist as long as you don't do anything about getting bullied yourself; heck, if I'm going to get beaten up for bullying you, I'll probably end up threatening you not to tell anybody and do something worse than just shove you around.
I can see where most people are coming from (and holy crap, how come you all get bullied in school?), but "an eye for an eye" isn't exactly the best way to go about things (even if it is school). Either do something about being bullied by changing your image or fighting back (or just live with it, it's part of being a kid). I've tutored kids who comes home beaten up because they thought the school could protect him from getting beaten up outside of school premises... nah
and factor: you can sue the school if you get hurt by that crazy kid with the knife, thats why you get into trouble when you do things that could potentially endanger yourself...
... and not running away from a guy who pulled a knife either means you have a bigger knife, you're wearing a chain mail, or you're extremely stupid