I used a demco tow dolly for three years before switching to a flat tow. Never once did I use the accessory switch or the seat belt for anything. Drove the car upon the ramps, strapped the tires down, hooked up the safety chains, with the vehicle in park, ignition off, key removed, and off we went. The only thing leaving your ignition on in the accessory mode will do for you is give you a dead battery at your destination on your tow vehicle.
2018 Phaeton 44OH
2017 Chevy Traverse Toad