Not alot of information needed to make a full determination so I have to make alot of assumptions.
Assuming that there is a reserve on the auction, the bidder, who has a 100% positives and a FB rating of 10 with a membership since 6/2000, I would say that the person is simply bidding by a couple of bucks each time to reach the reserve by bidding the highest amount they wish to bid on the item.
They are NOT bidding to force anyone else up, simply bidding in increments of a couple of bucks. Generally you see this with newbies with less than 5 FB rating but anyone can make a habit out of it.
I get these all the time on my auctions. I have never had a problem and I gladly welcome them as they add to the spirit of the auction and usually get others bidding up by a buck or two until bidding passes the reserve and the original BIN price.
Malcolm
Malcolm