Y'know, I certainly wouldn't pretend to answer for anybody else's dog, or jeep or anything like that.
Speaking for myself, what I own are cow dogs. These are the kind of dogs farmers use around here to herd cattle mostly, sheep sometimes. They are pretty clearly related to Aussie Sheps or Border Collies, but nobody here bothers with purity of breeding.
They are tougher than whang leather, agile, athletic, loyal and smart as hell.
You see them riding on top of 12 foot high loads of hay bales on 1 ton flat bed trucks, totally unrestrained, at 60 mph. You see them riding on the cross bed tool boxes in the back of pickups at 75 or 80 mph.
I would trust this breed to stay with the jeep through anything short of a rollover. I do not and will not restrain either of my mutts in the rig. I would also regard a rollover as an indication I went farther than I personally should have.
Other dogs, other stories.
Bone stock '81 CJ7.
"You can always see it coming. But you can never stop it."
-- Cowboy Junkies.