Agreed. We should always be skeptical of an individual's ability to beat the market.
Well, I should clarify that I think a smart bias-educated person can beat the prediction markets fairly easily - I doubled my (small) investment in the IEM just by exploiting some obvious biases in the last presidential election, and I know I'm not the smartest bear around. My doubt is whether he can beat the market enough: any sum of money CronoDAS has is likely small enough he would need really absurd returns.
Here's our place to discuss Less Wrong topics that have not appeared in recent posts. Have fun building smaller brains inside of your brains (or not, as you please).