I like to think I'm pretty scam-savvy, but it only takes a moment of the holes in the swiss cheese aligning. I saw a recreation of a movie prop that looked like a good gift idea for a friend and made an impulse purchase. Something was nagging at the back of my head and a couple of minutes later I had a sinking feeling that it might be a scam -- sure enough, a little research showed that the product photos were stolen, the original was a limited-run authorized item that sold for 20x what I paid, and I found a forum post where this scam item was being discussed.
The web site I bought from was a single legitimate-looking veneer page with most of its content lifted from templates, and there was no functional tracking or order management anywhere, so I immediately e-mailed them asking to cancel the order, to which they replied that they that the product was "good quality", "you can rest assured that you have it", and that they would charge me a 5% fee to cancel. So I opened a case with PayPal and they closed it saying the transaction was "consistent with my purchase history", whatever that means. I appealed and they doubled down that it was not fraudulent. There are no more buttons to press at that point, but I wrote back again reiterating all of the evidence that they were actively providing a payment service to facilitate fraudulent transactions (the scammer was still around and still advertising the same fake products) and after a long period of silence I suddenly got a refund.
PayPal is not on your side as a customer, especially if you're dealing with a professional scammer who knows how to play the game and string things out. I suspect what happened here was that they got one too many complaints, and if they'd been a little less greedy or more careful, they would have walked away with the bag of money.