I suppose it depends on what information was given to Christie's and what questions were actually asked.

On the other hand Sotheby's once has a nice Pantin four leaf clover weight for which the attribution was backed up with a comment about the UV reaction being the same as other Pantin weights. But, in fairness, after comments by some folk pointing out that the clover weight tied in much better with Paul Ysart equivalents, they did remiove it from the auction.
