Maybe I'm wrong, but NG is seldom issued ammo domestically. Look at past photos where they have guns, and like the photo above, the magazine well is usually empty. Two words: Kent State.

If the crap looks like it'll hit the fan, likely there is a truck with a NCO or Officer who can pass out ammo.

Secret Service will take the 'hit' on this when they move the swearing in to indoors. They'll be able to insist they wanted it outside, but were forced to hide in the basement.