People try to be slick to get their item sold first. (since the AH automatically sells the lowest priced item up first, which I think is unfair) then get played when someone actually bids that low.
If I want something sold first, and the price is a steady 20k, I'll throw it up for 19,700. Even if someone bids that low, it's only 300gil lost. But when idiots put it up for 15k...>:o