When they decided it was ok for players to make money, the reality is that it would be impossible to regulate. So no need to really do any investigations, that's all they'd be doing all the time, is investigations. NIL was never meant to pay for play but anyone with an ounce of foresight knew that is what it would become. And it did so immediately.
The biggest problem is players have all the leverage to negotiate pay for play because they can switch teams and play right away somewhere else. If they had to sit a year if they transferred, NIL would mostly work like it was intended. Schools would certainly pay players to get them on campus but once enrolled it would be up to the player to capitalize on his/her name, image and likeness, and the transfer portal would have about 10% of the players in it that it does now.