Yes, we were discussing an ad where a proof quarter for sale was pictured. The coin was cobalt blue, and the ad said nothing about that. Of course, the coin is not that color at all, but we wondered why the seller ran the picture and said nothing about it. I did send the seller an inquiry, but why do these misrepresentations go on? Regularly we see coins that are pictured as golden and such, and the seller posts no disclaimer. When questioned, a seller will blame lighting or the camera used. But why can they never simply clarify in their ads that the picture is misleading? Is this just a case of caveat emptor---buyer beware? If so, how sad.
Many people who sell coins on E-Bay are not professional dealers and numismatic photography is very difficult for many people. I see many photographs with white balance issues that make the coin look toned when in reality it is not. Personally, I put this type of stuff in the "caveat emptor" category. Learning how to interpret coin photos is more important than expecting sellers to provide disclaimers. And if you learn the former, you won't need the latter.
Being able to interpret coin photographs is an essential skill for the modern, technologically savvy collector. There are a wide range of pics, some are good and some are really bad. You see them all, even here on CT. When buying, know what different lighting techniques can do. A coin which appears white in hand can be anywhere from blue to red in a poorly taken picture.
Here is one we sold a while back that is as close to cobalt as I can come up with .... We called it Gorgeous 1968 S Jefferson Nickel Proof Colorful Toned
Quite a great Jefferson !! I have a '61 from a proof roll that looks like a million dollars and pleases me so much. I sent a message to the quarter dealer and they agreed with me, said they'd post a new picture. Aha, there is a Santa Claus after all.
Few aside photographic specialists understand the term "White Balance," or even that it's something which is adjustable. They accept whatever comes out of their camera as "what they can get." Never ascribe to maliciousness that which can adequately be explained by stupidity.