Because sellers haven't been able to leave anything except poitive feedback for 5 years.
Because, anecdotally, most sellers don't look at bidders' feedback before an auction ends. Or they sell at BIN, or the bidder snipes at the end. Any of these reasons won't warn a seller that the buyer is a NPB.
HOWEVER, opening a case against a NPB and closing it when appropriate will usually see the buyer given a strike. More than 1 strike in a seller selected period of between 1 and 12 months will see them automatically blocked from bidding or buying from all sellers with those blocks in place.
Far more useful than a neg or a negative pos. To me and others like me who fit paragraph 2.
