I'll leave Rick to speak about the rules. I can say it is VERY common for local College coaches, even D1's, to watch bullpen sessions at local high schools or parks. I know of a 9th grader who was throwing over 90 and even though no contact was allowed several schools had seen him pitch. He committed (unofficially of course) to a local D1 the summer in between 9th and 10th grade. From what I hear the coaches were relieved because having all that high power attention at their practices was affecting the entire team.