I would just say be careful. I have been a proffesor or on staff at 3 different universities/colleges and know that each one has a very different atmosphere when it comes to faculty/staff-student relations, even if in print their polcies were basically the same. At one it was not uncommon, although not publisized either, for students and faculty to date in situations where the student was not enrolled in the staff memebers courses, and certainly friendships were common and openly acceptable. At other places this was certainly not the case and a distance had to be maintained between Faculty and Students.
The difference between a pick up game of basket ball and an RPG is significant. The RPG is more social, and creates different ties.
Talk to a friend who works there about the issue, and proceed with caution. Personally I would think it safe to start as even an unofficial gaming club on campus than a purelly social gathering. The unofficial club might either become official or move off campus to the social, but a club is safer place to start.