there's no point in catching them, right? Well its an assumed out. The runners must tag up to advance. What SSR is saying is that once in awhile its possible to catch someone off the bag, not understanding that an out was called, and you can double them off. what do you mean by assumed? iirc the batter is definitively called out, so theres no force. but if you drop it some moran may freak out and think they have to get to the next base. Yep, that's my thinking. Guys see the ball drop and they instinctively take off for the next base.