I think that's a good impulse, but completely refusing the bid seems misguided. The current system seems like it favors predatory buyers over fair ones. If the

I think that's a good impulse, but completely refusing the bid seems misguided. The current system seems like it favors predatory buyers over fair ones. If the seller undervalues their item, trying to start at a fair price will get rejected. I don't know how you selected the [500 1500] envelope on price, but it seems pretty narrow. Couldn't you just warn the bidder that their bid is way above the seller's expectations (or current maximum offer) and then confirm they want to pay that much?