It really isn't complicated and doesn't involve morality or any other difficult concepts. If you
know something is fake and sell it you are committing fraud. Everything else is a matter of opinion. If you do not want to state an opinion for someone to rely on, then have a TPG look at it. If it passes, you can sell the item as a "XYZ Authenticated" item and let the customers decide whether to accept the TPG's warranty. I do that all the time. I do not second-guess the industry-accepted experts when it comes to things I do not know. If the TPG cannot authenticate it [not necessarily because it is forged; sometimes they don't have exemplars] and you don't want to stand behind the signature, sell it without warranty of authenticity and be prepared to take a radically lower price. I picked up this item from one such auction:
I understood that if the signature was no good it was my problem, not theirs.
A sloppy, incongruous, or hurried signature is one of the most difficult things to deal with. Below are two items unquestionably signed by the same HOFer. The first Lennox Lewis item came to me courtesy of a friend who got it at an HBO event. Lewis signed at a table sitting down when he had time to do it:
This Lewis card is one that I got myself at the Los Angeles presser for the Klitschko fight while the champ was walking from the ring to the podium to have his press conference:
No way will the one I got ever pass muster with an 'expert' or with anyone else, except perhaps an expert I knew personally and who would therefore trust me enough to stand behind the item. That's what makes collecting this stuff so darn difficult. It gets even worse when you deal with an aging athlete, perhaps one who is experiencing a physical decline. Like Muhammad Ali. Look at his signature from the 1960s and then the 2000s and it is like two different people signed.