Ahem, ... spits. 1. contain the public in their homes.. therefore the single gunman terrorist attack doesn't take lives in pubs, churches, nightclubs, theaters, etc. A 'non-event', zero FF attack.  the public contained in their houses.. keeps them safe from stray return gunfire from the criminals as they refuse to be arrested and instead decide suicide gun fight with the sheriffs, police, agents, National Guardsmen, US Military round them up and put them in jail awaiting trials and internment.   Also keeps the dozens of citizens cellphone cameras clicking off Facebook pictures giving away the clandestine round ups.