Most of us here are honest and stand behind what we trade. On used gear, unless the seller provides you with their original receipt, you have no idea how many owners there has been. There are some terrible original owners, who don't take care of things, so what does it really mean? When I buy used, I don't think I have ever asked if the seller is the original owner. I care more about whether they smoke in their room with the gear. Most warranties are void and if it is Bryston gear with a 20 year transferable warranty does not matter as much.
Last year I sold some Nordost speaker cables. I send them to the buyer in a plain DHL/UPS type box that had Nordost logo tape on it, that was from a pair of interconnects I had changed from RCA to XLR. He sold them later and claimed he had the original box. (He probably though he did.) When I sold them I claimed they were in very good condition, he claimed excellent condition. I was probably being conservative, so maybe he was not making an exagerated claim (or maybe he was)? He did an auction and he only got $15 more than I sold them for, so no harm done.