In California my wife had an accident with a car that didn't stop. Not being on the scene I can't say for sure, but the way she described it was clearly not her fault. She followed the car about 30 minutes to grocery store where the other (female) driver proceeds to get out of the passenger door. The other driver says that it is her third accident in a year or so and since the damage wasn't major either way would rather just forget about it rather than file a claim and probably lose her insurance. My wife agreed.

Long story short, other woman does file and fault is determined by the adjuster(!?!?!!) since no cops were called at the scene (never mind the other woman fled the scene). Adjuster decides my wife is at fault. Our insurance (state farm) which she has had for at least 15 years cancels us because she had a one-car accident 2.5 years prior (which they did a piss-poor, jerk-us-around job of never really repairing). So, moral of the story is get a cop on site to determine fault, even if it is tiny and don't be suckered by any sob-stories.