The short-stop would be cheating roughly 5 feet toward 2B to protect against the steal. She would have to have the discipline to stay put until the ball is actually bunted down before breaking to cover 3B. Even holding her position until the ball is bunted down, she has plenty of time to sprint over and set up to cover 3B before the runner from 1B gets there. Besides, the center fielder is sprinting in to cover 2B.