Vacating Batters box

Question
Sitiuation: Bases loaded. No outs. First pitch is wild pitch. runner on third breaks for home. Does the hitter HAVE to vacate batter's box as to not interfere with play? Or is he entitled to stand in box? My player stood there, put his head down, did not move. No play was made at plate. Run scored. Umpire warned that would be called for interference had any contact been made with any defensive player. Even though defensive player would have had to initiate it. Again, he did not move.
Thanks
Rob

Answer
This is a commonly misunderstood rule situation concerning the interference call.  The thing you have to remember about interference is that is ANY act, intentional or unintentional, by an offensive player that interfers with a defensive players ability to make a play on the ball.  With that being said, when the pitcher comes in to cover the plate he is attempting to make a play on the ball.  It doesn't matter who bumps who, if the batter is standing in the pitchers way and in anyway hinders his ability to make the play, he can be called for interference.  If interference had been called here, since there were less than 2 outs and a runner advancing from 3rd, the runner would have been out and preceding runners would have had to return to first and second.  As an umpire, I make it a habit of telling the batter to back up a couple of steps as I'm getting in position for the call at the plate and thus have never had to make an interference call on that play.  I hope this answers your question.