Violence at parties can be a problem even when they are held on campus, a college ID is required, and there's a cover charge (this story is not NPHC, but a step-show after-party hosted by an organization that has its act together):
http://www.thecrimson.com/article.aspx?ref=520381
I honestly don't know what more can be done, except to restrict party attendance to members of your own campus, which defeats the purpose of finding fellowship with students at nearby colleges.
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ROLL BLUNTS