It's actually the other way around - clubs will be banning kids from playing on HS teams, mostly in their senior year once they have made a college committment, this is already happening in soccer, I personally know a highly recruited soccer player from a big time LI club who's a HS JR and was already told he can't play his senior year (actually kind of sad), but once the club does all the showcasing and recuiting they want to be able to deliver the player in one piece