To prevent accidentally beginning turn by typing B when not intending to, please allow users to disable keyboard commands individually, or, add some sort of verification to make "begin game" a two step process. I actually would prefer both, just to be super safe. It is beyond annoying to accidentally begin turn in a game when one is simply intending to add chat.
Everyone who has ever started their turn in a game when they did not intend to would benefit from this. If the user can turn on/turn off each keyboard command individually, complete customization should keep everyone happy.