Well wouldn’t the troops be instructed to face their Commander in Chief and maybe salute as he went by where they were standing, then possibly turn the other way after he passed? What does it take, five seconds?
My wife told me it was during the parade, so that makes more sense. I thought they meant during his speech when he was looking out over his vast crowd of admirers, uh, I mean flags and the troops would be looking for trouble.
During a sporting event, the security people basically never turn to look at the game; they always watch the crowd.