Why would a bidder leave bids on four of my items and then three days later retract the bids??

[gussya]

After leaving bids on 4 items, and then retracting the bids 3 days later, with the reason being "entered wrong amount" from an experienced buyer/seller with 689 feedback - why?? 

Also, does anyone else think it would be a good idea for retracted bids to show at the top of the listing next to bids as (-1) and so on, and show the username.  That way it would be easy to check if that bidder has been doing that with other listings?  Cheers.