Without a wheel chock, a strap like the canyon dancer insures the forks don't shift/turn. I would not, however, recommend them as the primary tie-down, as they do put pressure against the turn signal buttons and could do damage. Used with straps as shown in the pics above makes for a good, stable bike.
The service manual shows the rear tie-down points are the frame members that come back to support the side cases. I'll have to check the grab rail (as shown in the pics above) as an alternative next time.
Anyone tie down the tires to the trailer? Always thought that was a must-do.