Sounds like a jurisdictional issue.
Schools should have jurisdiction and very little disciplinary power over anything happening on school property and/or during school functions - ONLY.

That is the way it was when and where I went to school. That's why fights were scheduled for after school hours and off campus.

If the players have a problem with each other, and incidents occur outside of school, contact the parents and let them deal with it.
If it occurs inside of school, let the school deal with it.

I was told as a child, that if I did anything at school that caused me to require "school discipline," I would be receiving much worse when I got home.

Too many "parents" are OK with letting the schools "raise" their children. Unfortunately, this requires schools to step-up because they know there is often too little discipline in the home.

Obviously, I agree with the OP - School Over-Reach is a growing problem - promoted by a growing lack of parenting.