From Robert Bowling via twitter: 

Robert Bowling ‏ @fourzerotwo

• Yes, double XP stacks during Double XP weekend.

think its quad yeah

Good question.  I think xp from kills goes to the weapon you kill with.  Like, if you need 500 xp to get to level 2 with a weapon, that would be 5 kills in a tdm/kc.  If so, double xp should correlate directly to weapons as well.  Maybe do a search to find out how weapon xp works.

I'm on double xp now. 10:14 am in Florida .

It probably IS boring shooting people that appear to be just running right at you, not shooting.  Shooting 5 feet to the left of you.  Getting stuck in doorways, etc.

9pm and still no double xp.........imma go buy a ps2....lol

Dang, that sucks, man. I'm in Virginia, and I have it. I know it's not NC, but it's close! Haha.

Look at your score in the lobby after a game. Then look at the last match summery and look at the top line XP only. Should be double what the lobby score was....