I remeber a thread on here a couple of weeks ago about this and it has happened to me.
I need a new charger for my mp3 player and have seen one on ebay. I emailed the seller to check it would work on my model of mp3 and then put in a bid. Hey ho another bidder has come in adn bidded against me even though the auction has run for a while.
This new bidder has bought 4 mp3 charges in the last month all in auctions where there is only one other bidder and the price has gone up. Got great feedback from the seller everytime who is my seller and I bet there was a second chance offer somewhere along the line.
Anyhow thanks to mumsnet I am going to do nothing and wait for the second chance offer