That's pretty much my standard response. I love the look on the face when John Q Public asks me what started the fire, I tell them "rapid self sustaining oxidation with varying intensities of light and heat".
This is true. I actually made one of the Tempo fires where a man was unable to get out of his car before it was fully involved. There was a huge class action suit against Ford and our fatal fire was one of the big pieces of evidence in the case.
My opinion would be if not intentionally set is electrical whether it was in a wreck or not we investigate thes and it is usually in result to a short in a wire.