Let me guess: Mom was out of town and Dad had the kids for the weekend. Dad wasn't too keen on feeding the ducks at the zoo or battling the crowds at an amusement park, so he instead opted to stage a sci-fi combat scene between his two impressionable young sons. It's one thing to play dress-up and go crazy with the hair gel, but it's quite another to equip the kiddies with imitation weapons and have them shoot at each other. Pirates don't fight with explosive machine guns anyway. If Dad's gonna undertake this sort of project, he could at least be historically accurate, no?