I dunno about Belgian f-16s, but with American M-61s in F-18s there is a whole lotta safety interlocks that say that is not supposed to happen. And like most mishaps it might have happened when those interlocks are intentionally disabled for troubleshooting. Only mishap like that I know of was more than one AH-1W where mechanics were trying to clear malfunctions and mistakes were made.
Well that and it is not uncommon for an incorrectly loaded sidewinder to hop off the wing and skip down the flightdeck upon carrier landing. No motor or warhead dangers, just a hundred pound chunk of metal covered in sharp things and moving fast.