How do you vet them? Just with a DD214? That doesn't automatically qualify them as honorable and competent. I wouldn't be surprised if the asshat with the bow and arrow qualifies as you've described. And how do you handle liability? Not just liability for the volunteers, but the liability for the police department when rambo does stupid ****. I'm just trying to think practically about how that would even work. It's something that can't just be put together in a day. Hey, boyz. Bring your DD214s and your AR 15s and help us out here. I guess I could see a situation desperate enough to do something like that. This ain't that apocalyptic.
Standing a line doesn't mean you have to have a rifle. I would be fine holding a shield up, wearing some extra body armor and letting the guys beside me handle the firearms if they put out a call for help from the citizenry. Just give me a striking weapon.