Is it possible the "enthusiast" may be a little to "enthusiatic" regarding the condition of a chip? I have had this happen to me several times.
I go out of the way to point out the tiniest flaw in my sales, yet, I have been sold chips called "Slightly Used" that looked like they were slightly used to drive a nail. I have paid extra for a "mint" chip and been sorely disappointed in what I received. For the record-never from a club member.

And it dosen't have to be THAT extreme. The idea is to get an unbiased asessment of the condition of a chip, rather than having to takle the seller's word for the condition.