Anakin and Obi-Wan have both lost their sabers by the time they are sentenced in the Arena. They're given loaners by N'Sync when all the Jedi show up. Hence, one has a blue one and one has a green one. Commander Courage's analysis is correct. Furthermore, Anakin and Obi-Wan both lose their own blue sabers on Geonosis. Obi-Wan when he is captured; Anakin's gets destroyed on the conveyer belt in the Droid foundry.