I sold a mobile phone and the winning bidder was a genuine account that had been used without permission. Luckily ebay spotted this and invalidated the auction. I later received an email purporting to be from ebay saying that the problem had been sorted as it was a mistake and I could now continue with the transaction. I then received one supposedly from Paypal stating that the money had been transferred and could I ship the item immediately. I also received 2 emails directly from the "buyer" asking me to ship it to an address in Nigeria. I was suspicious as I had just re-listed the item and I sent the emails to the ebay safety centre address for spoof and confirmed that they were fake. I don't know if this made a difference or not, but I sent a message to the username congratulating them on winning. I don't know if they then contacted ebay to let them know that they had not bid on the item. Luckily this was all sorted before I had sent the item but had I been less vigilant, it could have gone badly. The emails look very genuine. I' am sure there are genuine buyers in Nigeria, but I would advise caution when dealing with anyone from there. A quick confirmation message at the end of the auction and ensuring that all money is received before anything gets dispatched seems to be the best way. eBay did a great job in spotting this and sorting it out quickly. My only complaint is that they completely erased any race of the previous listing and I feel that I could have contacted the second place bidder to see if they were still interested. As it is, I've had to start a new auction.
To paraphrase and old adage; LET THE SELLER BEWARE!!!!!