Should auction houses honor all items that accompany their own LOA?

[Exhibitman]

This does raise an interesting question that I wanted to address separately: what do you feel is the acceptable limit on authentication? I like this from LOTG:

"We occasionally sell autographed items that have not been authenticated by third-party entities. In general, these are lower-value items. We will not sell a high-dollar autographed item that has not been authenticated. In the event that we sell an unauthenticated item, we guarantee the authenticity of said item for 90 days from the date of purchase. Should either JSA, PSA/DNA, or SGC, the only entities we currently recognize as authorities in autograph authentication, reject an unauthenticated item purchased from our auction within 90 days of purchase, we will refund your money. Please note that this does NOT include large lots of autographed items where a few do not pass. Also please note that we reserve the right to obtain a second opinion prior to providing a refund. Should our chosen authenticators render a favorable opinion on authenticity (at our expense), we will return the item to the initial winner."