Given the transfer of ownership could just as well have occurred by transferring the private key of the address, these requirements are going to get pretty hard to enforce.
If someone gave me a copy of a private key, corresponding to some bitcoins, I wouldn't consider it payment, as they still have the private key as well (meaning they could still spend the bitcoins at any time).
It's more like a "shared account" at that point.
I suppose if you try to extract the secret key and the token destroys it, it's pretty secure. Of course, you just lost all your money. I can't think of a non-destructive test.