Well, here in San Jose, we just had a good reason. A 55 yo driver guy hit a ped dude in an X-walk, got out of his car to help, and was beat half to death by the dudes buds. This might be a reason to stay in you car and call it in, but certainly not to leave the scene.
But I think the real reason* is* panic. You are not thinking straight. I do not think anyone logically goes “Well, maybe I can escape blame if I drive away”.
Oh, and one final thing: dudes- if it is a minor fender bender, and no one was injured, and both cars can still drive- take it off the road. You don’t have to block traffic with it. Take it off the freeway or off the main drag into a nearby drive way. Make sure the other guy isn’t hurt, note his car license #, then tell him where you’ll go to exchange info. IF you are both insured, and no one is seriously injured, you don’t even have to call the police (at least here in CA). Do call the Police if the other dude is driving impaired or has no insurance or ID. If anyone is injured at all, call 911.
A report does have to be filed with the DMV (here in CA), but your insurance co will do it for you- if you tell them, of course. If you both* jointly *decide the damage is so minor that even the insurance co’s don’t have to be involved, then the law would seem to say the Police/DMV do not have to be notified either. IANAL.
But the important thing is- get the fuck out of the godamn highway so you don’t get more cars involved! An easy way to turn a fender bender into a traffic fatality is to get out of your damn car in heavy traffic. (Oh, and the fact that the traffic won’t turn into a giant parking lot is a nice side benefit for everyone else) If you can- get it off the highway. It’s perfectly legal to do so, *if *there are no serious injuries, you both know that you’re driving just a short distance away, and both cars will still go. IANAL.