California has a law about mandatory reporting of accidents if the cost of the damage is over a rather small number, like $300 or so. My wife thought she was doing someone a favor by not calling the cops after a minor fender bender (other party said that it was their third accident and if they got any more points at all they would lose their license).

But, the other party did report it afterwards so there was no official police report to determine fault and thus fault was decided by the insurance adjusters (how f'd up is that?) who decided that *she* was at fault (even though at the time of the accident the other party had "accepted" fault, and pretty much was at fault).

Moral of the story, call the cops at the scene, no matter what.