I doubted we'd find much about his immediate plans; he was too smart to leave obvious evidence but even a player as conscientious as he made mistakes sometimes.
Game theory takes this into account.
In a "trembling hand equilibrium," a player can accidentally pick an unintended strategy--say, when you reach for a queen's bishop's pawn and accidentally move the knight's in error. If you release the piece, you've made the move, even if the consequences are the opposite of what you'd intended and are disastrous.
From Edge, by Jeffery Deaver