That's true. And it's also the case that no human escrow agent makes 100% correct decisions, so no system is perfect, which is why a market of escrow service types would be a good thing. The market can decide in aggregate what the best form of escrow is. I was originally trying to include an escrow protocol in the market, but now I see that a decentralized market protocol should be agnostic to that. It should merely provide a protocol to contact escrow agents, while preserving the privacy of buyer and seller, and the transaction details, unless they opt for a service that requires that info.