When I sell my used gear on these websites I certainly do not want an item returned. I describe the item exactly as it is and buyers should have the understanding that the used market is not a buy and try proposition. Speakers are the most susceptible to damage- through either under/over powered amps or through physical damage. When I sold my Thiel speakers, I wanted the buyer to pick them up in person. That person got to hear them in person and inspect them thoroughly. I certainly wouldn’t have appreciated him coming back two weeks later to return them because they didn’t sound good in his home.
Buyers must take responsibility for their decisions at some point. Where dealers offer money back guarantees, that’s great and gives us some assurance about the product and I wouldn’t hesitate to return an item on those terms if I were not satisfied. When it is a no returns or a no cash refunds deal, then I think real hard first before buying.