We were eating lunch one day and were observing our neighbor hitching up his travel trailer. It was not chocked and the front jack was up about 7" on a few other pieces of wood probably 2x4's .
He had a suburban and obviously not very good judgement. He kept backing up and pulling forward to get it aligned. I told my wife to keep looking. Sure enough he bumped into the jack and knocked it off the wood. I ate my last bite of sandwich and went out to help him out. Luckily "I" had a jack. The ground was soft and his jack sank 6" into the ground. Jacked him up and helped him hook up. I did ask him to chock the wheels first. I wondered if he would think about it next time he setup.
He didn't say much, thanked me and drove off.