The risk is then the HS coach is literally the kingmaker in the town. To some extent he/she may be that to some extent anyway but allowing the summer piece creates problems. What if you're a good player but, for whatever reason, the coach just doesn't like you or your style of play? You might as well move. At least if you are playing on an unaffiliated club team you have other chances to show what you can do and it is not one person's view dictating your future. On the other hand, if the club team also doesn't like you maybe it's time for tuba lessons in pursuit of the college scholarship.....