Years ago I volunteered to teach sailing to Girl Scouts at a lake near the Girl Scout camp. I needed to tow a trailer loaded with six Sunfish from the camp to the lake and back. At the time the only hitch I had was a little clamp-on unit I had clamped to my van's bumper. But I had nowhere to hang the safety chains. I put the trailer hitch on the ball and tried mightily to dislodge it and when I couldn't I decided I'd just hang the chains from the attachment straps for the van's gas tank-- just this once. I towed the trailer to the lake with no problems. We unhooked it and wheeled it close to the water for easy unloading/loading. But late in the day I was struck with a blinding headache and had to lie down for a bit so I had one of my adult assistants go get the trailer. Unfortunately, she had done some towing but was unfamiliar with hitches and failed to open the ball-hitch-- she just sat the closed hitch atop the ball and hung the safety chains on the gas tank straps (as I had told her). A short time later another of the assistants came rushing up to me and said I had to come quick. As we approached the scene I knew exactly what had happened. There sat my van in the middle of the main road with this big metal box (my van's gas tank) lying behind it. The fully-loaded sailboat trailer sat off the road with its tongue jammed into an earthen embankment. The state park ranger and township police were there by that time and asked what happened. For some reason they accepted my flimsy excuse that my assistant was unfamilar with hitches and had not opened it to put it down over the ball. They never asked about the safety chains or why my gas tank was lying in the middle of the road. But I have no doubt they knew the answer.
