Handle9:

Someone has always been at fault, especially with regards to insurance. For cars to hit each other someone has to do something wrong. It can be a complete accident but it doesn't make it without fault.

You're nearly right but not quite. Accidents, with more than one car involved can occur where there is no fault attributed to either driver. It's usually the result of a medical event and insurance companies payout for their own claimant. I know from personal experience.