Remote printing = fun
Most newer business-level printers (e.g. HP LaserJet) have the capability to print from a remote location, as long as you know the network address (and as long as the owner has the feature enabled). Which means that I could be down in Antarctica and print a prank page of some sort to a printer 10,000 miles away and the owner might not know where it came from (keep in mind that most of them DO keep activity logs, however).