Good move by the U of I for the following reasons:
10 injured, 3 hospitalized as fans storm the field at UVA
Husker player knocks Missouri fan unconcious
21 students injured, 1 paralyzed, during on-field celebration at the University of Toledo
73 injured, 6 critically, as Badger fans rush field
Intro from article in Sports Lawyers Journal regarding fan injuries during on-field celebrations
These incidents are not common, but you never know when something intended to be fun could turn ugly and result in tragedy. I am sure most fans have the best of intentions, but when you mix the capriciousness of youth, a good dose of alcohol, emotional visiting players that have just lost an important game, and thousands of bodies, it is impossible to predict the result. Best to be proactive in this case.
From more of a philosophical standpoint, I feel like the field is kind of sacred. The players and coaches have paid for the right to step foot on it through their blood and sweat. Fans have not. Celebrate with the players once they come out of the locker-room, congratulate them when you see them in class, but don't mob them after the game just because you want to be part of an "experience."