While resale of bicycles and components is a losing proposition -- well, that is unless you have a collector's item -- why would carbon frames or forks be any more suspect than aluminum, extra-light steel, or extra-light Ti ones?

Manufacturers Warranties (Trek, C'dale, etc...) are usually extended to the original buyer and are not transferrable regardless of what frame material is used. Like cars, the evaporation of that warranty is what causes 2nd hand bikes and frames to loose about 15% of their resale value as soon as you sign the credit slip. Some exceptions include Co-Motion's frames (lifetime frame & transferrable at least for tandems) and Calfee who will extend their 10 or 25 year frame warranty to a subsequent buyer for a $250 warranty transfer fee which includes an inspection conducted by Calfee: cheap insurance on one of the $5,800+ tandem frames. Of course, if the frame is 5 years old, you're only covered for the balance of the original warranty period.

Yes, I've heard the carbon horror stories (some would qualify as urban legends where a single event has been modified and multiplied countless times), but I can recall many frame and parts failures with the more traditional materials. In fact, I've probably seen or heard about more aluminum handlebar failures than carbon over the years, noting that carbon has a lot of catching up to do in terms of market penetration.

Bottom Line: 2nd hand buyers are pretty much on their own regardless of what they buy.

BTW: If anyone out there finds they can't sell their carbon frame, you can give it to me. I'd be particularly interested in ones with 54cm top & seat tubes.