I think gun owners should be accountable for their firearms. If you leave it in your car and someone steals it and kills someone, I think you should be held civilly accountable for not safely storing your gun.
So, citizens who are victimized by criminals should be held financially responsible for those criminals' acts? Would you include this idea of yours to the home as well? If some criminal breaks into my home and steals one of my weapons and shoots somebody with it, I should incur not only the financial damages caused to my home and the theft of my property but to the other victim's family as well? What you're saying is that the victims of criminals should not only pay for those criminals to be arrested, charged, prosecuted and imprisoned but, that they should also pay for the damages those criminals cause to others?
Let's add another hypothetical to this. If a criminal breaks into someone's locked vehicle, steals it and runs someone over with it... the owner of the vehicle, who's a victim of crime, should be held liable for the damages caused by the criminal?