I had a dog die in the back of a pick-up truck. My then live-in BF tied her and Zamboni to the front rail of the bed, nice and secure. But she was strong and pulled hard to the side, to get her face into the wind, and somehow, she fell over the edge. He was taking them up to the mountains to go for a hike.
Nicest guy, would never do anything "stupid" to endanger my dogs. He's an outdoorsman, raised on the water; he knows how to tie appropriate knots. But the dog was stronger than his knot. And he did do something that ended up being colossally stupid. My dogs always ride in seatbelts, dammit. But he thought they'd like being in the fresh air.
My dog DIED, tied carefully to the back of a pick up. If it can happen to me, it can happen to anyone.
Imagine being him, waiting outside my office at the end of the day, to tell me that my sweet scruffy dog was dead, that he killed her because for whatever reason, the dogs weren't in the cab of the truck where they should have been. Imagine the look on my face. Imagine how traumatized Zamboni was when her dear packmate, who had been sitting right next to her, broke her neck that day.
Why anyone would do this to their dog, their packmate, their family members is beyond me. I realize it was an accident. But it's been 14 years, and I don't know if I'll ever get over it.
V~~, perhaps your dh needs to know what can happen. I mean, this DOES happen. And I still feel guilty for the stupid way she died. And I still cry -- like I am right now.