Many years ago, a Flight Sergeant, RAF, was walking past an RAF Sqn Ldr, who was absorbed in looking somewhere else. Slinging a smart salute, the FS called out "I'm saluting you, sir." To which the Sqn Ldr replied, "And so you should, Flight Sergeant, So you should."
I remember, as an ATC cadet, a bus conductor being saluted by a passing squad. Scared the hell out of him.