I have noticed recently that items which are close to ending get a random bid which is extremely high and unrealistic. This therefore means that the bid wins and the sellers are ecstatic with their sale. However, soon they find out that-
1) the buyer is fraudulent and is not PayPal verfied.
2) the buyer had no intention to pay for the item and simply bids to mess up the auction and cause the seller to be charged fees.
3) the buyer wants the item to be shipped somewhere that you don't post to.
I admit that some of these bids can be accidental and some buyers do contact the sellers to inform them of their mistake.
It is unfair on sellers to have to re-list items again and file unpaid item disputes to get their final fee value creditted back to them.
Another problem with this bidding scam is that when a buyer does not pay, then the seller has to wait several days before it can be relisted.
I have noticed that this bidding scam generally happens with electrical items, such as mobile phones.
I think that eBay should be more vigilant and have a system which, if a bid for an item is extremely higher than its value, then it should not be accepted.