My husband was a soccer coach for our oldest child, and I was always amazed at the parents who just dropped off their kids and never so much as said "hello" to him before they left the field. He was always so afraid when the little kids would run up and hug him. He would try to hold them at arms length, and they would just try to get to him. It was funny in a way, but we were both so afraid that someone would claim abuse. He got into coaching because he enjoyed it and because we wanted at least one parent to be there all of the time. There were years of coaching where we didn't meet parents until the end of the year party.
I see this too in our baseball league. I always wonder what happens if the child gets injured during practice!