My buddies and I all subscribed to this theory as young kids in Texas, then one time some of us did a trip to the junkyard to get some parts and it was a graveyard of absolutely demolished pickup trucks. Shook us pretty good. The junkyard guy knew what happened to some of them, too, like this one where the passenger compartment was just a block of near solid steel apparently got in a crash with a Camry.

So I'm not sure "big car safe" is necessarily true.