I would be surprised if any college has ever kicked someone out for looking at LEGAL porn, even if it does violate the school's "moral standards."
I mean, you hear stories of Christian colleges kicking out students for finding out they were starring in (gay) porn, but do you really think no student at, say, Ohio State has ever looked at porn on the school's network connection?
Unless you are doing something illegal, your tuition dollars are pretty important to them. You are taking a chance, but I think, in reality, it is a pretty small one.
As a legal technicality note, I would like to see a school try and kick a student out for this, as they would likely argue that a student was using "the university's network" to access porn. However, a legal counterargument would be that a student is paying for access to that network, so they have a right to use it as they see fit, as long as it doesn't violate the law. Of course, honor codes and contracts could also come into play, but would a school bother for someone looking at legal porn? Not unless they has other reasons for wanting to be rid of someone.