If that happens, the NCAA would be placing undue/unfair restrictions on the player's choice of transfer schools.
-- Player finds himself in less than ideal situation at current school.
-- Player identifies an opportunity at a transfer school where he is potentially an ideal fit.
-- Player enters his name in the portal
-- Player is unable to transfer to said school because they've used their portal allotment, thus eliminating said player's opportunity.
I don't think this would fly, but I fully expect the NCAA to come up with some regulatory measure in the near future regarding portal transfers.
For now, let Jefe turn this **** into the Wild Wild West. Let the player decide where he wants to move.