Hopefully, the event will sell out quickly...and thus the Foundation would have enough attendance certainty to consider doing some streaming (free, or paid as thefiniteidea suggests) as a means for widening the reach.

Alternatively, what I've seen some companies do in order to give an event higher visibility without risking empty seats, is maybe livestream a keynote or two (or post them online soon afterwards) while leaving the rest of the talks unstreamed and unposted for a few months.  But in that case, as thefiniteidea points out, it's best not to announce such a plan beforehand, so as to encourage maximum attendance.  So my guess is that there will be 100% silence from the Foundation on the topic of streams until the event is confirmed sold out...which should be easy, given that Bitcoin is unquestionably the most exciting technology since the Internet itself, and the chosen location has the highest concentration of nerds/VCs/entrepreneurs per square mile of just about anywhere else on earth.  If executed and advertised properly, this event has the potential to be massive wrt. spawning new Bitcoin startups and generating millions in funding for Bitcoin ventures.