I don't see them getting a lawyer and even if they did, I doubt whatever NIL collective they sue would have available funds to clawback. They'd most likely just dissolve.
But let's say sitting out becomes commonplace and the pendulum swings to the other side. Let's say a future player starts doing really well and demands more money than the NIL committed since he's now underpaid and 'disrespected'.
Then they sit out to demand more. That's going to be what happens next.