it's reasonable to expect that a person know where their car is, but that does not amount to a legal requirement to do so, as you have admitted. In point of fact, you are not responsible for what other people do with your things. If you borrow a gun from me and shoot someone, I cannot be held liable for that shooting. Ownership may imply responsibility, but not liability.

Yeah, you left out a part of that.

"If you borrow a gun from me, and I don't know that you did, and you don't or won't tell me that you did... oh well. shrug" becomes your expectation of what should happen next.

"Oh sorry, you weren't driving your vehicle, and you have no idea who was, when it was involved in that accident. But you know it wasn't stolen. Guess there's nothing more we can do here, have a nice day."

You're arguing that because a gun or car is dangerous, ownership implies liability. There are few things which can be possessed which cannot be dangerous in the wrong hands, and a car is not actually intended for the purpose of murder, so one should probably not judge it by that standard. However, I did explicitly consider the case of an inherently dangerous object, so I cannot have left out that part as you suggest. I am really not sure what part of this concept you could possibly have an objection to. You know we're talking about a car, right, not a hydrogen bomb? Surely you can do better than that?

If someone is killed by your gun and you don't tell who, you will be jailed at least.

This is not phrased such that it can be said to be true or false. Yes, accessory to murder is a felony itself. Accessory to speeding is not, and being ignorant of the crime is the opposite of accessory. Would you like to rephrase your objections?

Car is dangerous. It's easy to kill someone by accident using car, just by pressing accelerator pedal long enough. Just compare number of killed or injured by a car and by a weapon. Car is still the most dangerous thing we have: http://www.vpc.org/regulating-the-gun-industry/gun-deaths-co... .