This is why I never put scans on my site that show the
registration holes. If I ever were to actually sell a cel
(hey! it might happen someday! ^_^) and someone where to
doubt the authenticity, I reserve scans of the registration
holes as proof that I do have the cel, and not just a scan.
I've also requested scans of either the registration holes,
or the back of the cel when buying cels off Ebay from people
I don't know.

Something to think about if you're ever doubting a sale. ^_^

Many Sharp Smiles,
--Drac  (working on a gallery update)