DD's team has a base runner on 2B. Pitcher throws a ball in the dirt and the catcher looses it momentarily between her legs. Base runner on 2B steals 3B when the throw down to 3B was late. Home plate umpire calls the batter out for interference because in his judgement the batter moved back in the box in an attempt to hinder the throw to 3B. Batter still had both feet in the box. I always thought the batter was OK, as long as she was in the box. Batter was about even with the plate when the pitch was thrown, so it is not like she was at the very front of the box moving backwards. Any of the rules experts on DFP care to offer their opinion?