What is your school's policies on kids hitting, slapping, and punching each other?

Do they have any policies in place with communicating things with parents?

My son was involved in an incident today that required a trip to the office with another child and I'm pretty upset I heard from my child about what happened, but no one called, emailed, or pulled me to the side to discuss the issue with me! So, I'm curious how other schools handle these things.