In a recent interview to promote the PLAY! A Videogame Symphony Concert, Audio Director of Bungie, Marty O' Donnell let it slip that Bungie had the option to let press play Halo 3 multiplayer at last month's E3 2006:
"Well a funny thing about that, we showed them and flew around in the trailer in real time, we were able to show how light reflects off the space-tether, you could see the expanse of the Forerunner construct and how it goes out for miles, something people don't know is we had the option to let the press play some multiplayer."
Aside from that, Marty also revealed that in the near future Bungie will have a behind the scenes feature on Bungie.net showing the process of creating the music, and the teaser for Halo 3:
" It's one of those things that is my decision, where I have the ability to want to do it or not since I am the audio director for Bungie and not just a hired hand. I have a hand in making the trailers, and help put in my own input throughout all that Bungie does in many ways. We are bringing something new out here soon though, it isn't a dramatic thing, it's just sort of a behind the scenes showing how we did what we did with the trailer, and we are going to show some more angles of the trailer."