As the scholarship athletes so if a kid wanted to leave and go to another school he’d have to get permission to do it from the school he was at and go through the same process as any other transfer. If they don’t want to let you go someplace else they can block you getting a scholarship, etc.

To me the only advantage to accepting a PWO is that it guarantees the kids admittance to the school, provided he can match the requirements all athletes have to meet, and he is guaranteed a place on the team.