Often shouted by shotgun-toting isolationists who discover that spiky-haired mutants or jack-booted thugs have circumvented the crude barbed-wire fences that protect their dirt farms from the dangerous riffraff of the outside world.
When I get old, I'll probably yell this at the neighbor kids. Not being a gun person, I'll have to find something else to tote. A giant crucifix? A broken umbrella? A commemorative statuette of liberty?