In "Soldier Dogs" they explain that many of the dogs in training are dog aggressive. They're being trained to find IED's, ignore gunfire, and keep the humans alive. Being social with other doggies is not a requirement. So if they're in the field drilling The crotch maneuver blocks the dogs vision long enough for the other dog to get out of sight. With the heat and heavy equipment the handlers don't need to be breaking up fights too. If I may clarify, I'm just suggesting that it's good to read the body language of owners and dogs when you're walking...I would give the same courtesy to other people. I almost never walk Sophie in our neighborhood because there ARE too many triggers...and it's not safe, I know that...even a block to the post office...and never after dark anywhere In comparison when we walk in the woods she is a social butterfly and has instant recall, unless you're a chipmunk she does wonderfully in quiet open spaces.