Well, yes it is indeed a gray area. The coin IS altered, but the trick involves a switch using sleight of hand. If the coin was copper and the trick done the same way, you wouldn't be asking if it was a gaff. However, if the coin had a secret hinge like a folding coin , and you could show a bend that way, that would be using a gaff. I think we would all be in agreement on this. So the question on whether a pre-bent coin used in a switch is a gaff is indeed a gray area.

Harris, wouldn't the spec feel the bent coin ?