Er, I think an explanation of martial law is needed.
By the time martial law hits, there is a strict curfew, and the military takes over policing duties, where they have ridiculous policing powers and all your civil rights go right out the window. There doesn't need to be "reasonable suspicion" of a crime, there just has to be "suspicion." A lot of crimes don't have a lengthy trial and usually get prescribed the death penalty, either by single gunshot execution, or taken away to another place, then execution. Why, they could suspect an attack, shoot your dog and burn your home if they caught you peering out the front curtains.
Anyway, the moral of the story is, if you're gonna carry around a weapon during marital law, make sure it's a big one, and at the ready. ...And that you have a few friends with you, also with big weapons.