Marking Items Sold

In the last few days I have had three seperate instances where I inquired about the availability of an advertised product, only to be told it was already sold. I don't mind this but in each instance the ad is still listed without being marked either sold or sale pending. One of these items is even a featured item at the beginning of the category. Since it only costs two dollars to list an ad, can't people just mark their items sold and just relist if the deal falls through. At the very least say that a sale is pending. There are enough ads as it is, without having to inquire after already sold items. Any comments?