For anyone carrying a load on a rear mounted setup not originally engineered into the trailer, I suggest using a locking cable to securely connect the load to the TT should the carrying structure or rack suffer a failure. I carry a two-bicycle rack using a receiver hitch I mounted to my TT's frame myself but I still run a cable through the bicycle frames to a substantial trailer frame member. That way, should my rack or receiver fail, the load will stay with my trailer until I can pull safely off the road. Damage to my property is one thing but avoiding any potential damage (or harm) to others would be my top concern. The locking cable I use also provides some theft deterrence when my rig is parked and I'm not around.