Thinking this over this morning, I have a feeling it will be up to the tow truck driver more than the tow insurance company. They all contract to local drivers, don't believe any have their own towing company. Even AAA contracts to local companies for service.
As for dogs in vehicle while on a flat bed truck....
Glad I have no desire to visit FL again, been there done that.
All I could find was "unattended
in a parked
vehicle with inadequate or no ventilation
I would never leave my dogs with no ventilation in a vehicle being towed on a flat bed at around 30-45 mph (depending on the road). Heck I drive around sometimes with them on a 90 degree day with just the windows open, they don't suffer and love to have their heads poking out the back window.
And believe me, I would keep a very close eye on the back where the truck was sitting on the flatbed.
And interesting fact, what I read does not state leaving the AC on is ok...nitpicking yes, but that could include those who leave dogs unattended in a motorhome with the AC running.