I haven't done any further research on their 2FA, but when I came back to the game on a new rig it did ask me for a code despite 2FA not being enabled, originally. I did enable it yesterday so I could continue to trade and I haven't been asked to enter anything else. I'm assuming if you've authorized your PC beforehand it doesn't need to do it again?
I'm more irritated that there hasn't been any word about the update aside from Steve's tweet, which is basically nothing. I didn't expect the update to come out today, and I'd bet money it won't be tomorrow, either, but can you at least inform the masses of what's happening? I mean come on now.