I've only seen this once, done by a Presbyterian minister at a funeral. The funeral was for a an openly gay Christian friend of mine who had spent most of his short life struggling to fit his religion and his sexuality together, and the minister was like something out of "Breaking the Waves" or a kailyard novel. He made that gesture as the coffin was going into the furnace, and it looked more like a a curse than a blessing. But the guy's family didn't act like it was anything out of the ordinary, and it was their show, so I assumed whatever meaning it had for them took precedence over any Nazi associations it might have for me and the assorted leftie friends in the congregation.