Yes, I believe it is. I would expect with enough similar complaints that any 163.com email would be blocked from using PayPal. Shopping through Google search, I had ordered a replacement swimming pool pump since ours was failing. I got a normal UPS tracking number through PayPal notice, checked it randomly and all seemed fine. Then I got a notice that the package was damaged and discarded by UPS. I call UPS to ask a live person about letting me inspect the item in case it's still functioning, and two reps both told me the package was actually 'rubbing alcohol' and the bottles had leaked thus soaking the box. One guy in a loud facility, mentioned something about coming through Amazon, but nothing shown my Amazon account. UPS notified the seller, but no known reply at this point. PayPal wants to give benefit of doubt to seller by saying they'll watch the UPS tracking for 10 days looking for any further movement in the system. Uhm, they were just told and confirmed that the product was not correct, plus damaged and discarded by the shipper. But apparently I still have to wait 10 days for their dispute decision with or without seller's reply.
So.. out of desperation to find a pump for my wife to still use the pool this summer, I thought I found another on a website with US contact info. All was fine and looking normal for a checkout cart, until the PayPal receipt popped up with being paid to a 163.com email address. I'm thinking; Oh crap, here we go again. So I instantly notified PayPal of the suspected scammer with screenshots of the purchase process and how it switched within PayPal. I now see a notice of shipment, but no tracking number of course before PayPal is responding to this 2nd issue with 163.com sources.
