Seriously though - you do have a school like Clemson where fans do gather on the field after games. It is part of the tradition and not really "storming the field". I've seen similar situations on the high school level, where it is more of the fans gathering with the football team in support - win or lose. Those situations, because it is a common thing are generally orderly, and fans remain in control.
But because over the years we have put up fences and such and not allowed the activity with the excuse of protecting the field, players and fans - we are left with situations where in moments of high emotion fans get carried away - and because it is something they are not allowed to regularly do in an orderly fashion - chaos reigns because they are doing a once in a lifetime thing.
Sometimes the madness is the result of the rules being broken when if the situation were different, the madness would not occur.