Thanks to relatively low crime rates, UNLV isn't in dire need of very strict law enforcement. Other than the flood of police at the beginning of the year as students are arriving to school for the first time, you generally don't encounter UNLV police. Obviously, if you commit a more serious offense, the story might be different. Police response rate is fairly quick at UNLV, and incidences of more serious crimes are usually investigated immediately and resolved quickly. Other than that, the enforcement levels are pretty lax. This, like all things in life, has an exception. Police are known to be there when you least expect it, such as when you're doing something you're not supposed to, so don't think you can do whatever you want on campus.
In 2004, a UNLV graduate was arrested for making a speech with his pants down. Though the graduate student claimed his free speech rights were violated, the problem the police had with him wasn't the speech itself but that he spoke with his pants around his ankles. Things like that don't escape UNLV police officers' attention. So, as long as speakers keep their clothes on and do not get violent, the campus strictness is lenient.