I have heard that selling bitcoins on Ebay using paypal is very risky. I have recently listed several small amount bitcoin sellings on Ebay and indeed received some scammers. Fortunately for me, paypal blocked most of them before I even received the money

I am wondering if it is a good idea to have a blacklist somewhere that we can check if a buyer is a scammer. Most sellers on ebay won't sell their coins to new ebayers and user with bad reputation. So creating a scamming account will be time consuming if we can have a such list so that every seller can have a check before sending the coin. Ideas?

to find trustworthy buyers.
Of course there is no guarantee but it is better then to sell to a complete unknown party.