"So in the example with your shirt," says Meritxell, "the other person just says out loud 'I can make 10million gold pieces with that short' and you just say out loud 'I value it one million gold pieces' and then they do some math and figure you'll accept a trade of 5.5million or trades of less with less probability. But what stops them from saying in the first place 'I can make five million gold pieces with that shirt' when they can make ten."

"So in the example with your shirt," says Meritxell, "the other person just says out loud 'I can make 10million gold pieces with that shirt' and you just say out loud 'I value it one million gold pieces' and then they do some math and figure you'll accept a trade of 5.5million or trades of less with less probability. But what stops them from saying in the first place 'I can make five million gold pieces with that shirt' when they can make ten."