If they transfer to your rival, they should have to pay you interest plus penalties and fines.
1. No one cares about the player alone. We care about the player at our school.
2. This fulfills a crucial part of their student-athlete experience — learning about commitments and contracts.
NIL needs more than regulation. It needs an overhaul. How someone could pocket $1MM and then transfer after only playing a few plays or even a couple games is beyond me. You given the money because of the school you played for; not because of you. Boosters would especially agree with that sentiment.