I used to work with a guy that flew F105s. He told me a story one day. He said that the opening on the Jet fuel tank intentionally had a very different shape than the opening on the tank for water injection. That was, of course, so some numb-nut could not possibly put jet fuel into the water tank. Well, one day he was sitting writing a report in his office that had a window facing the runway and suddenly a big BOOM and the concussion almost shattered the window. An F-105 blew up on the runway apparently just as the pilot cut in the water injection system. Seems they found their numb-nut. Some guy fueling the aircraft was positive he was supposed to put jet fuel in that tank with the funny nozzle, so he scrounged until he found enough gear to make some weird adapter so he could get it in!