Rated R movies aren't allowed on campus, and your not allowed to watch rated R movies at the local theaters.
How do they know? If you are of age, what is stopping you from going to the movies with friends? Do they have a movie police person there at the local theater? Or even worse, is there a Liberty student representative spying on the students?
That just seems bizarre for an off campus rule. I understand on campus, but off campus is just nutty.
You agree to abide by the rules. The hope is that the students that go there and agreed to follow the rules will. But if people see you out at an R rated film and know that you are a LU student they may very well tell an RA they saw you. Once again though, by choosing to go there, you choose to abide by the rules. If you don't, you run the risk of getting in trouble.