I don't know about the U.S. but it happens in UK student unions all the time.
Really? Hard one to provide evidence for I know but any links? Back in my days (yeah OK they were still called gymnasiums back then) there would be a committee that would book the acts and usually they were up their own arses political activist types (I may or may not have been on such a committee) but didn't actually try to dictate what the act could or could not cover.