Hi - I've had a terrible run of NPBs lately. I always file a non-paid item case so that a strike is issued. Doing this disables the feedback option, though. I don't understand how a buyer can get false positive feedback for non-payment if a case has been opened and a strike issued. eBay policy says they may suspend a buyer, but I think putting appropriate blocks in place is the best protection, although there's no way you can completely avoid the scourge.