Why somebody hasn't set up a
transparent authentication service that employs a huge database of known transactions + AI (or,
Mechanical Turk) is beyond me.
'Lenny and his loupe' may be enough for a grading service, but there are FAR better tools for authentication if anyone cared to use them. I'd love to buy a graded card knowing EXACTLY what databases were searched (examples: ebay sale date range, auction house list, known provenance chain) and if any red flags were raised.