Not sure how it works at other schools....but for what it is worth, part of the NIL collective agreements at UND requires players to sign an NDA as to what they are receiving. Violating that voids the contract. Great in theory (and so far in practice, though admittedly new), but remains to be seen the long-term effects.
On the football side, where there is obviously a disparity between some players it is not an issue nor is it even discussed. However numbers are likely fairly small compared to the large NCAA schools and numbers out there. Different space and competition than hockey but I who knows what the true numbers out there actually are on that side.