They used this rule in the Italy vs Dominican Republic game and it was awful. I felt horrible for the how tough Italy played tied going into the 10th and then, to have a man on 2nd against THAT line-up felt it was completely unfair.
Reality is, batters take WAY too much time in the box. Umpires should force batter to be ready to hit within a few seconds. They step out, get signs, adjust something...then adjust something else...step in the box, step out and adjust yet something else and suddenly...4 pitches into the at bat, you are looking at 3-5 minute AB. HORRIBLE!