I recall the old days at uni when documents would be sent to a print server - a desktop next to the printer which you would log into and release the print job, with the appropriate payment docked from your account.
The technically-minded spotted that the printers weren't actually USB printers connected to the Print Release Stations. They were very basic network printers open to everybody! The machines were simply configured to send print jobs to the room's release station rather than the printer. The release station then forwarded them on.
With that discovery it was trivial to print a diagnostic page from the front panel giving you the IP, then you'd "Print to File", open the printer's spooler in Explorer and throw that file across the network direct into the printer's queue.
This discovery was fortuitously timed ahead of some rather hefty submission deadlines!
Just before I left the spoilsports replaced them all with fancy MFPs with an integral print release interface, so not so easy to bypass the print release and send jobs direct to the print queue (given the state of printer firmware, there was probably a way of hacking around it, but I never took the time to try as I was on my way out).
Biting the hand that feeds IT
