A real tragedy for the man’s family. But an important reminder on safe firearms handling. Having a loaded rifle freely floating around in the back seat does not sound like a very good idea regardless of whether or not the safety is on.
Rule 3 violation???
Likely a violation of law, too. In my state it is illegal to have a loaded rifle or shotgun in the vehicle. Of course, loaded handguns are legal.
I’m sorry but, WHAT A STUPID WAY TO DIE. Did he have kids? If he didn’t he is a winner for a “Darwin Award”.