As a postscript to why I'm so OCD about all this. I once had a large Uhaul trailer break free of my truck in the mountains of N. Ga. The chains broke and the trailer took off down the on coming lane of traffic and finally ran off into the ditch just before hitting a couple in a car head on. I had been towing boats and trailers for years before that without a second thought. That was over 30 years ago and I can still fill the knot in my stomach as I saw the trailer pass me in the oncoming lane and I can still see the faces of the lady and man in the car as they watched this trailer coming at them. Since then I do more than needed to make sure I don't have to go through that again.