The farmers I associate with care a lot about their animals and I expect them to take the same care with mine. As a rural person I judge people based on relationships and reputation and not on how much insurance they have. I'd trust any of these people to haul a horse in a big-ass trailer than I would trust myself or my wife.
Judging by the number of horses my wife hauls, most horse owners don't have their own truck/trailer. Which makes sense: for most people, the trailer won't be used very often, and hay is usually delivered by the farmer, so don't need a truck for that.
How did we get so far OT?