When in the air force as a weapons troup, we had to test the armament systems to ensure they would work when needed.
After each test was completed, for a "me" reminder (we always documented in the aircraft forms, but sometimes the forms were under review and were not on the plane) I would put a blue oyster cult symbol on the lower left side of the switch panel with a grease pencil, small, but visable, so if I climbed in I would see that the test had been completed.
Well, the symbol is kinda like a cross with a dot in the middle and the bottom leg is a backward/upside down question mark.
I got a complaint from the flight chief, and was told to stop putting the mark on the panel anymore.... they thought it was some kind of evil cult sign....
After telling the crew chiefs of the planes what it was, and that the band sang "Don't fear the reaper", they told the pilots, what it was and why I did it.
A month later, the flight chief told me there were four right ups in the forums that said "no reaper sign on weapons panel".... LOL
I had to check to make sure we had tested the planes ......