I had not seen that video before but in 1956, when I was 16 years old and driving a 1946 2-door Chevy with a bumper clamp hitch, one job I periodically had was to haul garbage to the dump on a single axle trailer. The first or second time I ever hooked up that trailer, I had 2 barrels sitting near the back of the trailer; negative hitch weight, had to pull the tongue down to hook it up. No problem at 20 mph, but when I moved up to 50 mph, violent fishtailing scared the dickens out of me. I did know better than to hit the brake, just let off the gas and finally got it back under control. But I can tell you that's a lesson that will stay with you the rest of your life.