They're not rigged, but there is definitely a strategy to finding them. It's pretty much how James plays the game. Hunt the daily doubles, then work bottom to top to make sure your competitors cant catch up because there's not enough money on the board to catch up.
I think Brad got really pissed last night at the end of the first game when the Final Jeopardy topic was US Politics. They announced the topic and Brad kind of threw up his arms like, "Seriously?" It could have been an opportunity for James and Brad to catch up by doubling up, hoping that Ken might not double up or even miss the question...instead it was US Politics so all three contestants doubled up, essentially making Ken the match winner just after the first game. Not only that, but it was an incredibly easy question.
When they came back from commercial, Alex was like, "Just a reminder, the winner of the match is the combined total of both games. So even though Ken won big last game, it's still anyone's match!" James had some sort of sarcastic, smartass quip after that though about how Ken already had it in the bag.