We had a similar setup at my university - printing to a lab printer was disallowed from a machine that wasn't physically in the lab. The printers had routeable IPs, so I'm guessing they did some kind of whitelisting at the printer itself.

The problem was, we were a Sun campus, and my tablet PC ran Linux. So I could SSH in, open up StarOffice, and hit Print on a document - all from the tablet PC in the crook of my elbow - then walk into the lab and pick the documents up out of the tray.

I never got in "trouble" for this, per se, but I did have a lab technician once look at me as if to say, "that's not allowed..."