Whether you want to deem someone a scammer or not makes no difference. You need to run your business with as much security as you possibly can, and when you accept Paypal from someone you know nothing about, you are taking an unnecessary risk. Someone could be the greatest person in the world and has done $1million in business with Paypal You don't know that, you know nothing about them so you are putting yourself at risk. Verified or Non Verified if someone does a chargeback they will honor it, I have been on the phone with Paypal above the customer service level, the manager told me, "It is an intangible product, it's not us, it's the banks" I said what if I showed you screenshots and invoices of when I purchased a domain and it in my account, and then show you it in their account ? Doesn't matter sir there is no protection to the seller of an intangible item, the bank will honor the chargeback.
You use FlippaEscrow, Sedo Escrow Only, Escrow.com, EscrowHill.com etc... But every time you do a paypal transaction for a domain name with a stranger, if you get to keep the payment, you got lucky. If you get scammed no one is going to back you, not Paypal, the banks or the registrar.