It's a pretty good idea but for example the seller set a delay of 24 hours and the highest bid get the item and what if the one who lead the auction decide to cancel the bid after 24 hours (there is a rule who says : D) If you withdraw a winning bid at the end of the auction you must pay the auctioneer 20% of that bid.) So we will need a system of automatic trade. So the seller and the buyer will get a notification of a trade so the seller will have to accept the trade ofc and the buyer will have the choice between canceling his offer and accept the trade, so if he cancel he will be debited 20% of its offer and this money will be sent to the seller.