Saw this yesterday: http://img141.imageshack.us/img141/6375/253fdffd813441a6af712a5.png
If it was a stunt (seller got a friend to bid), it would still be an expensive stunt with the 10% sales fee. But looking at the number, I think it could very well be someone who typed 520 without deleting the 220 first from the bid box. I remember bidding an extra digits on something due to input lag repeating a number and clicking on bid too quickly. It was one of my costlier mistake in my earlier days of playing SK. But that doesn't compare to 3 extra digits.
It would be nice if, perhaps once a month (to prevent abuse), it is possible to retract within 30 seconds of the bid.
They just need to get rid of the input text box lag. Such a standard user input control, I'm not sure how it doesn't work right. Even when trading someone some CE, I have to press one key at a time and wait, press the next etc. If I just enter it on the keypad then it'll come up with some series of digits that resemble what I entered.
P.S. I have paid 5100 for 3 blue shards. Was originally 5, I pressed backspace then 100 and submitted the bid. But the input box understood the entry as 5100 nonetheless. A smart seller would include no buy out just to take advantage of this mechanic.