I just wanted to add my own experience regarding someone who is already on the list:
decompositions52
The person made me an offer through ebay Messaging, for an item I had listed on a regular seven day auction.
I accepted, but wanted to try and do things legit to protect both of us. So I canceled the original auction, and setup a Fixed Price listing so he could just go and BIN.
I send him the new link. He then replies to me that he specified the amount he offered was with shipping including. But he never mentioned that or made any statement like that. I tell him unfortunately I can't do the deal with shipping including.
So I'm out, it looks like .60 cents. But it was just a big waste of time.
Not the most egregious incident, but beware if you choose to deal with him. Be VERY clear, almost childish, so there is no miscommunication.