Yeah I was wondering about that. They're kind of putting a lot into this with the 24 hour stream of the game going live. Could go pretty badly if they mess it up.
my guess, is that they have some sort of local server set up or something, if not I'd be amazed if it wasn't broken/laggy
You would think that after the Sim City fiasco and Blizzard running the largest MMO in the world for almost a decade now, that they would know a thing or two about server stability and could account for this stuff. We will see though.