Probably an apocryphal story, but - at Chicago having been told that there was a delay in departure clearance, 50 or so in the queue, the controller announced a further delay. "****" says voice on r/t. "Aircraft using profane language, identify yourself" declares controller. "Speedbird 123, it was not me who said "****" ". "Air France 234, I certainly didn't say "merde" ". "Lufthansa 345, I also didn't say "sheisse" " etc. etc.