Ok, now I know I was a bad person when my children were growing up. Every year the schools would send home the rules. The parents were supposed to read them and sign the booklet. Well, I did read them and toward the end they had a paragraph worked in about how they reserved the right to use corporal punishment at their discretion. I had seen them abuse that permission and they like to drill holes in boards to whip the kids. I was having no part of that. I crossed out the paragraph, initialed it and whent to the school. We had some words and they understood that if they used the paddle, they would have it shoved in one of their orifices. That was plan A and plan B. They called me when they had a problem and I handled it. I was pretty strict and would not allow my kids to disrespect their teachers.
I have found it is much better to get to the point with them. Of course that was quite a few years ago and "my wife has since showed me the error of my ways."