I used to manage a U-Haul center, they will install a hitch (we did a lot of them). You just can't rent a trailer in you don't have a hard top. I had someone once who tried to rent with a jeep but we couldn't do it. He came back later with another vehicle, which I didn't know about until he returned the trailer with the jeep. I probably would have done the same thing had it been me, but you are liable if you wreck and destroy the trailer, even if you purchase the optional insurance.
I agree it is a stupid rule, but due to confidentiality agreement, I can't say any more.
