The mystery is solved. It was indeed James D'Ambrosio who was occupying Boosted J's seat. He had dropped about 7,000 chips to Hoyt Corkins by the time Smith showed up, and that just wasn't going to work. The floor decided to let Smith and Corkins start from the top with even stacks. D'Ambrosio has now walked over to his correct seat in front of Bertrand Grospellier, and their match has commenced as well.
Across the room, Jesper Petersen is also in his seat now, and Jason Mercier finally has someone to play against.