When people place repeated bids against themselves it's usually done in order to deter other people from bidding in the belief that they don't stand a decent chance of being able to get past the multiple bidder. The reality is a lot different. I have seen evidence of this not just as a buyer but also as a seller with people doing it on items that I've listed for sale on eBay, so I have seen both sides of the coin, so to speak.
Basicallly what happens is that the multiple bidder raises his maximum bid by very small increments over and over and over again, thus creating an illusion that he's got loads of money stacked against the item, and that even if you get past the first bid you won't get past the second one, or maybe even the third one if you get that far. I've actually found this out by winning auctions and then going back into the bidding history and clicking on the option to reveal the autobids as well as the manual bids, and it subsequently shows up every single bid on the bidding history. As a result of that I've been able to work out my opponents' bidding strategies, and by memorising their coded User ID - ie: two random letters with the rest of the User ID starred out - plus the maximum amount that they went to on previous auctions, whenever I've seen their coded User ID on other similar items that I've been bidding on I've been able to remember where their cut-off point was, thus helping me to work out how high I need to bid in order to knock them out of the running.
As you can see from the explanation given, this tactic can work fine if the multiple bidder can deter other potential buyers from placing a bid against him and he then ends up winning the auction at a relatively low price, but when he comes up against a more determined opponent who makes a mental note of what he did in previous auctions and who can remember his previous maximum bids for similar items then this is where his strategy can often work against him.
