That doesn't make any sense. If the university was genuinely concerned that the posters really were mad bombers, they are obligated to have police arrest them,

That doesn't make any sense. If the university was genuinely concerned that the posters really were mad bombers, they are obligated to have police arrest them, evacuate the campus, and search for the bomb they believe exists. If the university did not genuinely believe the posters were mad bombers, then throwing them out of an event for being college students telling dumb jokes to each other is a huge and unjust overreaction: they should do nothing, or at worst quietly contact them and ask them to cut it out. Splitting the difference and merely throwing them out of the event is pointless and matches neither option. Of course, all this is irrelevant because the two weren't thrown out because the University was concerned about a bomb threat. This all happened because some random anonymous person complained to MLH that the postings made them feel "unsafe," and instead of telling that person to go pound sand, MLH and HTN cooperated to enforce exactly the same foolish zero-tolerance policies they were joking about.