Not necessarily. Same thing happened during the Olympics. The "media" hyped traffic and the city advised people to stay off the streets. And they did.
Will be interesting to see if today is more crowded. I just dropped my g/f off at LAX and there was zero traffic - but 8:30am on Sunday normally is light. I'm betting today will be a little more busy as more venture out. I was about to head to Zuma but then thought better of trying to get back on PCH later in the day. We'll maybe just head 10 blocks west and surf there