It sounds plausible, but our experience so far is that cheating is very rare. Out of hundreds of markets, we had our first clear incorrect resolution yesterday.

But the argument is not simply that people won't cheat often. The argument is that people will choose to bet in markets where the creator is trusted. Even if the majority of creators cheated, users would react appropriately and flock to the ones who don't.

It's just like how you purchase goods and services. They often have a chance to keep your money without providing what they promised. But in practice, they can't run a long term business that way.

By the way, even in our play-money currency, the market creators earn a fee on the traders' profits.