* They have a new account, and have no Marketplace reviews.
* They want it shipped and will pay extra for shipping. (While some real sellers will want it shipped, most will come by to pick it up.)
* They do not try to low ball you or even negotiate. (Facebook sellers are notoriously cheap.)
* There is a sense of urgency and very responsive to messages. (Most Facebook sellers are not instantly responsive as they have a life.)
I have also seen scam sellers appear as well. They sort of do the same thing:
* The price for the items are amazing, a steal.
* They always ship, often for free. You can never pick it up.
* They are very responsible to any messages.
* The account is new.
Whats disturbing is Paypal didnt investigate the issue at all.