Re: Study?
I agree with you amid your concern about self biasing 'studies'. Since sponsored studies never find anything bad about the sponsor's product
Alison selling an item that might appear to have once belonged to Brad would likely fetch lower offers. Or selling a more male oriented product might well generate the feeling that there was something not quite right.
In this case the offered item appears to have gender neutral but was it and was all of the advert wording, its placement along with all other factors genuinely 'right'. Could a female selling a gift be seen as a distress sale item? So reverse sympathy got applied.
The item should have sold for very near the face value, less any postage or other costs, I wonder why no one got bids that were closer to its apparent value? That for me is a real aspect generating doubt.