I don't see why it wouldn't be, what with the last few all being webcast. Apple is eager to promote the HTTP Live Streaming technology, so my guess is that they'll use it any time they can.
Pretty sure they don't care. Apple follows their own road, sometimes they strike gold (everything iOS, laptops etc...) sometimes they miss (mice, Apple TV gen 1, etc...) but it's almost always a good show.
They make stuff they like. If you like it, too: buy it. If not: sod off. Their damn-the-torpedoes approach is what makes them so engaging.
I suspect that if it's not webcast it's because the main presenter (Cook?) might not be as experienced in giving presentations (as Jobs) and doesn't want the pressure of the live broadcast weighing on him.
That said, I think Cook did a wonderful job in Back to the Mac, but that was a smaller event and he wasn't the main presenter.
EDIT: Back to the Mac was announced as live stream 3 hours before the presentation (http://t.co/evl5Qwu), and the September iPod event the night before (http://t.co/r73jXfu).
