The idea is interesting but getting the software right will be really hard and without it been effortless everyone will end up sat back down taking notes and it'll become an expensive whiteboard/screen.
This is very true, i'm imagining someone sitting at their surface "ummm wait, its not going up, oh oh my bluetooth was off"... "wait now it's saying I don't have permission to project on this screen" "oh you need to talk to Jim, he'll set you up an account"
I don't think this will be the case, as the Surface Hub supports so many graceful Fallback Options. It even works as a dumb Miracast Receiver, if all else fails.