You don't tie down for the good, easy trip, you tie down for the bad trip. You want the vehicle to still be tied to the trailer like it started with, after a spin and two rolls.
Bruce
I agree I would but as I think more about it I am not so sure it is needed. After two rolls it would still be attached to the trailer - not in very good shape but still attached. (Of course even with a rear strap you could say the same thing - it wouldn't be in too good of shape after two rolls but still attached.)
I thought the reason for tying down a load was not to protect the load as much as to protect other people and yourself from the loose load hitting them or you.
TBS
Huge difference. Dolly converts the car into a towable piece of equipment where the rear wheels of the vehicle are part of the trailer system. Same as a stiff hitch. No different then latching onto your trailer and hauling it down the road.
On a trailer, the vehicle turns into hauled equipment where proper securing techniques need to be met in order for the vehicle to stay attached to the trailer in case of an emergency situation or accident. In this case, the back end of the vehicle is Unsecured
If both front tires are held securely in place and the steering is locked how is the backend going to move around?
That's also why there is chains for the rear, they aren't meant to be tight but to prevent the vehicle from moving too far around the trailer in a major incident.
Washboard? Pothole?
The front straps, and even the steering lock, aren't meant to prevent the rear from moving.