This guy.
https://www.ebay.co.uk/usr/bestiebmx?_trksid=p2047675.m3561.l2559That was the guy I bought my Morales from (a black one, before I got the one I have now) and he tried absolutely everything to get me to pay by BT. In the end I gave up. Turns out I wasn't the only person he tried that on either. For some reason I didn't leave him any feedback at all, but I wish I did now.
That's not mine, but he clearly tried the same trick on that guy. You buy, you pay, he refunds you and then tries to get around Ebay by making you pay with BT. I really don't know what condition he has, but I suspect strong narcissism.
That said people like that (who think they are a law unto themselves) are usually pretty easy to spot on Ebay because they are the ones breaking all of the rules. Which usually means I just don't buy from them in the first place, as it's usually very easy to spot. I've never never been taken for a penny, but only because I don't fall into traps or play games.