I don't think having paypal protected you as a seller more because it completely depends on where the buyer opens the claim. In my experience, most buyers opened a claim through ebay, not paypal. I think in all my years of selling, I've only had one open a paypal claim. In that case, I lost, but the buyer had to pay the return shipping.
Also in my experience, at least in the US, if a buyer claims fake, or really anything else wrong with the bag, ebay will side with the buyer if you decide to let the case escalate. They don't get involved in questions of authenticity. It doesn't matter if you have proof from a dozen authenticators.
I've only had an absolute scammer once, who forced a return and then returned something that wasn't the bag she bought, but it was cheap and ebay allowed me to keep the money, while also giving her a refund. Later she apparently did the same thing because she was kicked off of ebay. I had one or two other returns in which the item wasn't returned exactly as it was shipped and I had to eat the loss, but it wasn't a total loss, just missing some small parts or with a bit more damage than before. The biggest loss with most returns is the loss of the money I spent to ship and the money I had to pay to get the return back.
