The cause of the Trabing Fire has been determined and it wasn't arson. It was car exhaust. You can read the details in this article. I'm now on a CAL FIRE mailing list and got the news late last night but am only now getting the chance to share it with you.
This gives me the chance to reinforce some things I've said here and in person as well.
First off, I know I've commented on the potential inaccuracy of early news reports. In the case of the Trabing fire, I know I read early reports that indicated the fire was caused by someone, but they didn't necessarily indicate it was deliberate. The wording was actually rather vague. Over the next few days the news media fed on itself and the cause went from being uncertain to arson. This is a great example of the fact that early information - even a few days after an event - may be wrong.
Secondly, this reduces the likelihood that we have an arsonist running around. Sure, it's still possible, but now we know a major fire people thought might be arson caused wasn't, and that's something of a relief. I'll sleep a bit better.
And finally it's another example of how we unwittingly do things that cause risk to ourselves and others. Car maintenance is critical to avoiding fires, particularly in extremely dry conditions like we currently have.
