I don't see what harm a few negs causes a buyer, as long as they have a decent number of positives. In fact, a buyer with a perfect feedback is asking to be abused. At some number of transactions, most buyers are going to encounter some problem(s), be it intentional (fraud) or accidental (lost in shipping). Since negs are mostly retaliatory, at some point, anyone that doesn't have a neg could be a wimp.
If you contact a seller with a problem, they can easily see your feedback score. If you have no negs and a couple hundred positives, what kind of message does that send to the seller?
I can understand a person with only 10 positives being reluctant to get a negative. But after say 100, 1 negative, to me, means the buyer is a real person, in the real world.
I'm not certain that 1 out of 100 is either a good, or bad record. When I got my first neg, for a couple of days I thought I was wearing The Scarlet Letter. I was certain no one would sell to me. IT MADE ABSOLUTELY NO DIFFERENCE. In fact, one seller left me a positive saying that the person that neg'd me was a jerk.
What is this obsession (hope that's not too obsessive of a word) a for a perfect, or excellent, feedback? Is it important that sellers think we're perfect, or very good, buyers? To me, perfect feedback for a buyer means a perfect target.
The feedback system isn't flawless, but I haven't heard of anything better. It does seem to work for the more abusive sellers. Sometimes it only takes one buyer leaving a neg, and others will follow.
P.S. Does anyone know for certain that the ability to leave feedback is exactly 90 days 0 hours 0 minutes 0 seconds after the end of the auction? If I can't get satisfaction after 30 days, or indication of a refund, I neg or don't neg and walk away. Life is just too short to wait for another 60 days seeking revenge by sniping a negative.