Judging from the policy, it could also be argued the rules are there to protect the student organizers. A lot of people don't seem to realize that regulations surrounding extend beyond age restrictions. Similarly, a lot of people don't realize that insurance coverage is a factor whenever an organization is involved (and, of course, insurance companies will add additional restrictions). If things aren't done properly, the university and the students will be liable.

(Note: I am not suggesting the university isn't trying to protect their own interests. I am suggesting they are doing more than protecting their own interests.)