Well technically speaking I think that the NCAA actually kind of encourages it since its policy is that a scholarship is only a one year commitment from the school to the athlete. Aren't all the program's scholarships basically available the next year if something/one better were to come along. In an environment where more and more players are leaving early/ier it seems like it would make it all the more likely that someone is going to get recruited over...even to the point of not having a scholarship available for them when they in fact want to return and you can bet it won't be the borderline NBA prospect that unexpectedly decided to return that will lose his place on a roster.