I thought there might be some stress issues, but all your posts have convinced me to NOT EVEN THINK ABOUT IT!
I could always throw the bikes in the bed of the truck, however, the scooter needs to remain upright. Guess I need to travel without a shell (not desireable due to security), find a shell with suitable clearance, or perhaps explore the idea of a hitch receiver mounted at the front of the truck.
Thanks to all for the quick and straight forward responses. These forums continue to be an outstanding resource.