When I was in the third grade, a couple of buddies and I were goofing around during math. Mrs. Olson called the three of us up to get hacks. Joe got the first one as Blaine and I awaited our turns. The whack of the paddle across Joe's posterior didn't catch our attention quite as much as her breaking the paddle. When she replaced her paddle two days later, it would have been unjust to spank me. I did my work and kept my mouth shut. By today's standards, this would be considered abusive. It did affect my psyche. All the way into college, I did math during math courses -- all because of the hack that Mrs. Olson didn't give me.
I wasn't so lucky with the broken paddle when Mr. Baines explained why I shouldn't throw a basketball across the gymnasium, or when Mr. Seger explained why I shouldn't run through the hallways in school. Today I understand the dangers of these things, but, for a long time, I didn't do these things because of the painful lessons I was given. Basically, it boiled down to this: do the right things for the right reasons, or do the right things for the wrong reasons. Either way, we were expected to do the right things.
Schools today do little to teach kids anything about real life. Social promotion policies don't encourage kids to learn what is being taught, or to get jobs done. People, generally, don't get promoted for inadequate, incomplete, or incorrect work in real life, but they do in school. Likewise, suspension for disruptive behavior or fighting is not punishment to a child. It is an easy way to get some time off. Both of these rules violations should be punished with extra work, more time in school, and assignment to unpleasant tasks -- much like what will happen if they do these things in real life.
Many parents are against corporal punishment, and that is fine. My own experience, though, is that many of the lifelong lessons I learned were painful, and I'm better off for it.