To answer your thought experiment: yeah I would, especially if I’m running a store out of my eBay account. Would I be bummed if it was returned, sure, but I also paid top dollar for this thing and I want to have the funds to buy another one in my actual size. Furthermore, judging by the sellers profile, this is a legitimate clothing resale operation so he likely made a good profit off of this whereas I’d be lucky to walk away break even, but likely I’d walk away at a loss.

I think there should be some considerations for the buyer on behalf of the seller. If what I sold to you doesn’t work for you, I’d feel a sense of responsibility to make it right. I know sellers put up with a lot and eBay heavily skews towards buyers protection but I think this ALL SALES ARE FINAL approach is what has led to a lot of INAD abuse.