"Reminds me of the time when ..." printing a file with some patched up negative page count actually upped your printing quota in university.
The system would of course refuse any single job that took you over quota but, if you wrote a script that pounded a few jobs slightly below quota right after each other, two or more would get through, underflow and you'd suddenly have 65k pages left.
I know when you left the school you could get reimbursed for any remaining pages left on your ID but I wasn't crazy enough to try that. 65k * $0.05 = a chat with the police, I'd guess.