Wee Stevie, one of 56(F)'s navigators in the early '80s, went flying one night, leaving his car keys, F1250, cash etc. in his SD cap in the locker room....
Came the next day and as he showed his F1250 to the lad on the gate, the latter burst out laughing. "What's so funny, airman?" asked WS....
To which the lad merely showed him the F1250 - a little chinagraph work (courtesy of J***y U**n ?) had transformed it with beard, glasses, long hair and devil's horns. He did at least see the funny side!
Back in the '60s, a chap at some nuclear research place got fed up with being required to wear a photo ID on his coat whilst at work. So he modified it with a different photograph....
...of Nikita Kruschev! It was several weeks before this was noticed, whereupon he was promptly invited to find a new job.