"Feedback left by a user who provided eBay with 
false contact information during the transaction 
period (as verified by eBay), and cannot be 
contacted."

This is the most useful feedback removal policy. 
I used it to remove the only negative feedback 
left by an immature eBay buyer that I encountered 
a while ago. She loves to use the tactics of 
telling the sellers that she had sent out an 
imaginery personal check for the eBay items after 
the auctions. And at the end, when the personal 
check didn't arrive (because she hadn't send it 
out to begin with), she would leave negative 
feedbacks blaming the seller for not being 
understanding when she lost money over a lost 
check.

A lot of deadbeat bidders are just bidding for 
fun, so the information they provided to eBay are 
most likely false. And once you can verify that 
you cannot contact them through their phone 
number or their address is fake, eBay will remove 
their feedbacks.

--
Cheryl