Personally I've only ever experienced it once, although at that point I had yet to place my bid. The bidding was really high prior to my own bid being placed, but when I placed my own bid in the dying seconds I won the auction for less than the highest bid that I'd seen beforehand! After paying for the item further analysis of the bidding history showed that the highest bidder had retracted his/her bid literally seconds before the end of the auction, the end result being that I won the item for substantially less than I would have had to pay had that bidder allowed his/her bid to remain.
With regards to bidding a price up in order to find out a rival bidder's highest bid, if a seller was going to get an accomplice to shill bid the price up I wouldn't have expected him/her to do it in this way, as if the seller was indeed trying to find out your maximum bid then it would look far too obvious. It may well just be the case that the seller was a bit spooked by a newly registered bidder with zero feedback suddenly bidding with an offer that resulted in him/her becoming the highest bidder, especially if it was a high value item that you were bidding on. Some sellers can be a bit apprehensive about selling to buyers with newly registered accounts and zero feedback, so if that's all it was then you probably haven't got a lot to worry about, other than the possibility that one of your opponents who may be waiting until later to place a bid in the dying seconds may well have seen your maximum bid and now knows how much to bid in order to outbid you.
Going forwards the best way to prevent this type of thing from happening to you is to refrain from bidding early on in the auction, and submit your bid right at the end of the auction. That way nobody else can try to place a really high bid and revoke it in order to find out your highest bid, and if you do decide to place a bid in the dying seconds and it subsequently becomes the highest bid then the closer to the end of the auction you can get your bid to register the less chance there is than your opponents will be able to submit a higher bid before the end of the auction. Having said that, however, it's not necessarily the last bid that wins - it's the highest bid placed, regardless of when the winning bidder submitted his/her bid.
