Probably depends on your city ordinances, but I think as long as it's on private property and not on a regular sidewalk next to a public street then it's up to the building owner/tennant.
I made that mistake a few years ago when going to a roller derby bout at the coliseum. A couple of friends and I parked next to the building on a very wide, very out of the way section of the sidewalk. I wasn't thinking about the fact that the coliseum is city owned, and we came back to parking tickets. The parking lot was free, so it's not like we were trying to get out of paying. They were just being #$%*s.