That is a nice article on the pro day and the last paragraph confirms everything that I said. The large school must give its permission to allow specific athletes from small schools, but it makes sense to allow a few athletes of particular NFL interest b/c it adds to the number of scouts and their interest. That's what I said before you provided the article.
That article also says that the other small school players may be asked to wait until after the big school has completed their pro day. Why do you suppose that is? B/c keeping track of a lot of players going at one time in multiple stations makes it very difficult for pro scouts to focus on just a few athletes. And is distracting. Not to the players, but the scouts.
Typically, each team sends one scout to a pro day event. The scouts are involved in timing and measuring event results. If a scout is at the 40, he can't watch a player competing at the broad jump, and so on. The more players, the less ability to focus on each player.
As I said, the Gophers allowed nearly 100 athletes to participate in the past. 40 times were used as a hurdle to see who would continue. That process takes a long time. So a player runs his 40s and waits for more than an hour to complete his next event after the cut is made. That's not good. Then, as I said, the events and scouts are spread out while athletes complete the cycle of events, and scouts aren't able to focus on just the Gopher players.
Adding a few small school NFL prospects is no big deal and probably good, but adding large numbers as the Gophers have allowed in the past is dumb.