Liability wise not a good idea. But as far as rules go, they can come in and work out regaurdless where they have graduated from, but they cannot "coach" students unless they are a school employee. They do not have to be a paid assistant as long as they are employed by the district. I think its great as long as the kid coming in is not trying to put a notch in his belt by beating up on a high school kid. Some districts may have a policy against it, but when I checked into it a few years ago, that was the explaination the KSHSAA gave me.