The early comparaters were very easy to fool, they only read one side, and kinda like an old person with cataracs, if the size and image were there it took it. Weight didn't mean anything until they got more advanced. Even the comparaters that were used right before the conversion were not that sophisticated, but were much better that the late 70's early 80's stuff. Even the modern scanners used for Tito's and bill validators have been beaten repeatadly. I guess no matter what they come up with there is someone out there who will figure out how to beat it.