This type of question begs for an authoritative reply from an eBay representative, but sadly they seldom bother. I'm not a seller but I'll appreciate sellers' opinions on the issue.
Some sellers declare a "No warranty" or "No returns" or similar conditions in their listing for some items. I'm referring specifically to items that are listed as used but in good/perfect condition.
To give a hypothetical example: Suppose a used camera is listed as being in excellent condition, but with a no returns/warranty clause. Suppose further that the buyer finds that the LCD is not working or that the lens is cracked. Is the buyer protected by eBay guarantee in such cases?