Good guy with gun needs to know if other guy with gun is good guy with gun or bad guy with gun so he can decide whether or not to shoot him.
http://politics.blog.ajc.com/2014/07/02/on-new-gun-laws-first-day-a-draw-down-in-valdosta/
http://politics.blog.ajc.com/2014/07/02/on-new-gun-laws-first-day-a-draw-down-in-valdosta/