Auction house initial bidding rule last hours

Can anyone explain the thinking or logic behind the rule that with most auction houses that you cant bid on a lot if you have not initally bid on the item by the last day or a certain time on the last day?
I am trying to understand why a rule like that is set. You would think if someone was out bid on an item they may go for another but if they havent bid on it by a certain time they are not allowed. You would think it would help drive the prices of other items up.Are they afraid the auction will go on and on for extended days?
what is the underlying logic?
thanks for the explination here

You part of the reason in your post. The other reason to generate early bids. They know that most people will not bid until the very end of the auction. Because of this, they require that you bid before "close" to be eligible for the real action and provide early action on lots to try and get other people interested. It wouldn't look very good for an auction house to have most of its lots unbid upon near "close".

Baisically, it helps drive early interest in lots.

Jay

I see makes sense.
Thanks Jay