That is certainly a nice theory, and it's the one schools generally try to apply, however badly.
The problem comes in when you begin counting the number of people the bullies hurt while you wait for them to come around. And considering that many never do, just flail around till they get old enough for criminal law to apply, you begin to see a bright side to paddles.
Of course if we do allow schools to physically punish students, the privilage will be abused. Anybody that doesn't think that principles will let their prejudice guide their decision over who gets beaten need to check into a mental ward.
In the end it becomes one of those pick-your-poision choices. Would you rather see students abused by the principle or by the students?
Jay