One of my most cherished photos is of my grandfather, surfcasting out into the water on Block Island, in the 1950's. Hes shirtless, wearing a pair of army chinos (that he got courtesy of WWII), and a tie threaded through the pants loops as a belt. Hes got it knoted and hanging on the left side of his pants. And I have to say, he looked damn fine, and I am not saying that because hes my granddad. Just such a classic photo, so all-american. Some people can pull it off, some cant. I think the key is not having it look like an affectation. If you are all dressed up, and then decide to use a tie as a belt, it might not work. If you are hanging out, and it looks like you just grabbed a tie and used it as a belt, I think it comes across as total nonchalance, stylish but not giving a damn at the same time.