Apparently, the line "I was burning that f*cker And stringing my black flag high" was enough to bring in police. According to Missouri State's Expressive Activity Policy, the Bear Paw is an area on campus that has been designated a free speech zone for all people regardless of their connection to the university to express themselves.

However, expression that is obscene, defamatory or incites violence is not entitled to First Amendment protection and not permitted by the policy. [We won't go into the PC exceptions to these exceptions either but Punknews has a thought about it. - more on this story