If you want to get thrown out and possibly have the cops and/or security called, then yeah. Back when I worked there, we didn't allow people to copy stuff off the machines. We had some issues with people taking songs off of iTunes.
Just thought of this while reading the reply. If you're lucky, you might be able to take it to an Apple store and have the Genius Bar restore it for you. Despite some of the opinions around here, some of the Geniuses are actually really nice.