A lot of folks might already know this, but I was stunned to learn that eBay doesn't boot non-paying buyers. Heard from a guy today who got stiffed a couple weeks ago by the same buyer who won't pay me. He says that he notified eBay and also was able to put in feedback--the icon is green as if it is positive, and it counts as positive, but you can write anything you want, which in this case was "Beware, he didn't pay me." Any rate, this guy says that beyond blocking the guy, he has also set it up to block all bids from buyers who haven't paid twice or more. Huh? How many times can buyers refuse to pay before eBay does anything?
Buyer can have that removed if he asks.
Setting up to block buyers with two unpaid items is the strictest policy you can set.