Sounds like this is a regular move of his. This is from the Cardplayer.com updates blog on thw WSOP:
http://www.cardplayer.com/tournaments/l ... 848?page=2
"Brad "Yukon" Booth had a swift exit from this year's World Series of Poker Main Event. On a board that was queen high, Booth made consecutive bets of $3,000 and $8,000 on the turn and the river. His opponent check-called the whole way and called the $8,000 bet on the river. Booth's opponent showed Q-J for top pair and Booth mucked his hand, having presumably bluffed away a large portion of his chips. Booth was eliminated shortly thereafter when his opponent turned a full house against what he said was pocket aces."