I walk anywhere on campus and I get WiFi.
I think most of the dorms here have wireless, but there are a couple that don't (like the one I was in last year). Their reasoning, I guess, was because it was close to some residential areas and they didn't want people tinkering with their network. I thought that was pretty stupid since they could just walk on campus and do the same thing...
Anyway, there are probably some big fields or something where you can't get wireless here, but I know all of the buildings with classrooms have constant access.