You know, I'd say it is like selling a used car. The buyer could jack you and drive off without paying, or the seller could jack you and take your cashier's check. But we have all sold used cars, or similar, and that was to total strangers. At least on INGO people have history and ratings.
That happened to a buddy of mine in high school many years ago. The prospective buyer sitting in his Corvette he had for sale, listening to the engine run, popped the clutch and took off. Never recovered the car and the female accomplice took off in the car they arrived in, which had no plate. You never know.