If they know the figure in a guide is inaccurate, I say it is unethical to quote it without comment (I would say "the 5th edition of __ Guide says there are 12 known examples, but I have seen more than 50 at a time so I suspect the Guide is incorrect."

The question could be asked: how does a seller "know" the figure is inaccurate? If they have more than the number in the book, they know. If someone told them there are more in existence, then it really depends on whether the seller believed it.

Imagine that a guide book says there are 12 known examples of a chip, and I e-mail a seller who quotes that figure. My e-mail says: "I have 100 of those, but you say there are only 12 known examples." Or "My friend has 50 of them." I don't think it would unethical for a seller to continue to rely on his information rather than my unproven assertion.

That is why eBay does not monitor ethics, and why the club can do a great service to its members and others with its ethical standards.