Yeah, what you're saying is not acceptable and has been the subject matter of many lawsuits, if I'm not mistaken starting with BFL. You pay Bitcoin not USD. The bitcoin just happens to have a USD value which has fewer daily fluctuations than Bitcoin. If you are selling a commodity and don't want to enter into a contract to sell it at 50% under what you paid for it by accident while you sleep because an exchange got hacked or the CEO of Bitcoin goes to jail (   ) you peg your prices in fiat. OGNasty was selling coins for $1750 worth of Bitcoin. If the trade never happens, you're entitled to your Bitcoins, not USD. What you're saying is completely unreasonable. Bitcoin is Bitcoin whether it has a USD value or not. If a trade doesn't happen because he runs out of stock or whatever, his obligation is to make you whole and refund your purchase price. You didn't give him $1750, you gave him $1750 worth of Bitcoin and are entitled to your Bitcoins back, not the fiat equivalent. In 10 years of trading here, I've seen verrrrrry few cases where people have explicitly stated that the transaction would work the way you are expecting it would, and I've seen verrrrrry many scammers try to play this card. It isn't an accepted method of trade by the community.

I'm pondering what the legal implications would be for someone operating the way you suggest OGNasty should have. I'm not certain here, but I believe that would make you an illegal money transmitter. Instead of doing a commodity > commodity exchange, you're exchanging their commodity to USD and would be remitting to them USD then exchanged back to BTC in the event of a refund. Just make purchases with the intention to cancel because you think the price of BTC is going down, and you've successfully shorted BTC.