There's actually even more to it that didn't occur to me at first glance. Many times a player in second will wager low enough, such that if both they and the person in the lead miss the question, the player in second will win (because the player in first has to wager enough to stay in the lead if they get the question right). But the person in second just watched Chu wager for the tie the day before. If they think Chu will do that again (and why not), then now the correct play is to wager everything for the tie. And now Chu wins if they both get it right (because it's a tie), and he also wins if they both get it wrong.
just watched Chu wager for the tie the day before
It's better than this: they tape them one after another, so it would have been fresh in their mind.
http://mentalfloss.com/article/54853/our-interview-jeopardy-champion-arthur-chu
I'm not sure I've ever seen such a compelling "rationality success story". There's so much that's right here.
The part that really grabs me about this is that there's no indication that his success has depended on "natural" skill or talent. And none of the strategies he's using are from novel research. He just studied the "literature" and took the results seriously. He didn't arbitrarily deviate from the known best practice based on aesthetics or intuition. And he kept a simple, single-minded focus on his goal. No lost purposes here --- just win as much money as possible, bank the winnings, and use it to self-insure. It's rationality-as-winning, plain and simple.