I always suspected E-Bay when I would put in my max bid (and it's an oddball number so I don't get beat by a penny) let's say $42.76. Shortly after another bidder (without knowing my max bid) bids $42.77. I say something smells.
This makes utterly no sense.
1. Seller does not know your max bid.
2. Ebay automatically puts in the next minimum bid no matter how high the other bidder bid. So even if the bidder bid $5000 the number ebay is showing is the $42.77
3. The minimum incremental bid for something that's $40+ is not $0.01.
So, no this is not shill bidding if your bid goes up by $0.01 or by the minimum incremental bid.
I noticed this type of behaivour from an ebayer. A few years back when I lived in S. Texas, I use to bid on hog hunts. This ebayer cought my curiosity. He would usaully start out a hunt-item with $1 with no reserve. But a few hours before the bid ends, it jumps to a little less that the price that you will have to pay if you bought it as "buy it now". It happened on ALL of his hunts. Funny thing is he has a 100% feedback. I hunted in his ranch once and actually enjoyed it.
This is normal ebay behavior. People will bid up to but never over the buy it now price. People prefer to bid near the end of the auction. There is no evidence of fraud here.
I caught a guy selling small engines on e-bay, doing this.... the same couple of e-bay user names (each with 0 transactions and some silly "123" kind of name that no one would pick for themselves) was bidding on several of his auctions at the same (just how many $500 Honda engines does a guy really need). I turned him into e-bay, but I doubt they did anything, as sellers are their source of income.
Ebay cares about shill bidding trust me.
Ebay is crawling with shill bidders, more now that it's impossible to get a handle on other bidders. Ebay doesn't give a hoot about it, because it brings them more money.
Again Ebay cares about shill bidders. How do I know? My friend used my account to sell a multi-thousand dollar camera because I have great feedback. That dumbass then used his own account to bid on the auction because he was scared the price would be too low.
I got suspended for shill bidding.
Shill bidding gets easier and easier to detect the more often it is done. The problem is whether gunbroker has a system to detect it. Ebay does because they are rich. They have incentive to detect shill bidding because providing a fair system in the long run gets more customers. Just like why online poker websites publish their random algorithms and try and provide a fair place to gamble.