In HKG during a wheel change, the local engineers, evidently not bothering to go up to the FD and get the pins, used some self made wire coathanger contraption instead. The F/E, doing his subsequent walkaround in the dark, missed this contraption and seeing no red flag in the high up lock in the dark, accepted the aeroplane. We spent a jolly hour flying around trying to get the main gear to move- it worked well! The poor F/E was thrashed within an inch of his job!
It's astonishing how familiarity breeds carelessness.