Yeah, this is Nick Bollettieri's thing, which started with tennis. Many of the top American juniors destined for the tour play at this academy at some point. And it's really not just limited to Americans, as Kei Nishikori (Japan) and Maria Sharapova (Russia) both attended and are among the most dominant players from their respective countries. I really don't see much wrong with it since it costs a crazy amount to attend, so it's only a very select few that are getting the privilege. As NavyNuke said, this sort of thing exists in other facets, but I guess those aren't usually purely competitive (music and military).