Ads with "Checkup"

In many cases,it's an item that is still under factory warranty to the original owner,but the warranty doesn't
transfer to the second owner.

It has been my experience that these ads often mean the product was recently sent in for repair and the owner has decided to sell the item.

I usually take it the same way as robert8409. I'm sure there are cases like Kinsekd, but I beleive they are in the minority. Maybe I'm just a glass half empty kind of guy, but I also belive it was sent in for repair and the owner decided to sell upon return.

well, I suppose any buyer could ask for a copy of the receipt showing all work performed.

Pushes the bounds of believability IMHO. Goes great with memorable lines such as "box opened to inspect contents only" or "selling for a friend".