Interesting......
Now uhaul says you can tow a vehicle with another as long as the lead vehicle is the same weight or heavier than what is in tow. They also have universal hitches to bolt on to any vehicle.
Curtis and other manufactures makes hitches for vehicles with no tow capacity. I guess that can be used for a bike rack, etc?
My main concern would be to test the brakes and leave more room for merging and other actions. I too would try to go the speed limit if its seems like a load on the vehicle.
Me, I love renting vehicles and getting the extra insurance.