At the risk of outing a current (but non-card) auction, here's a good example of why non-snipers get hurt.
A zero feedback bidder placed 4 bids in 7 minutes and walked this one up from $200 to $400+.
I know it will go for much more, but it looks like Mr. zero feedback is trying to find the other guy's bid.
http://offer.ebay.com/ws/eBayISAPI.d...m=190336391115