Early in my career in the Air Force I served on the base honor guard team. We would perform funeral services often outside the area of our base. On a long road trip we decided to stop at a service station restroom to change into our uniforms prior to arriving at our destination. While we were changing into our uniforms, a knock was heard at the door. I opened the door a crack and said in response to the stranger's puzzeled look, "Changing of the Guard".