I seem to recall that somewhere they said that they feel that they've pretty much covered all the aspects of California Extreme over the past couple of years, so there wouldn't really be much to gain by filming more stuff this year.
It's not something like E3 or PAX where you have multiple new games and stuff to show off.
From what I saw they were there as fans (of the games). I had such a great time at CAX. It wasn't about press conferences, or sales, or hype, or marketing, or personalities. It was about playing games. Tons of games.