Small mistakes can make big problems

I know an experienced RVer who made a similar mistake. He hooks up to the spigot with a wye and then hooks up his city supply with one hose and then he connects the tank flush with another. He had finished setting up camp and they decided to go into town and left, what he neglected to notice is the shutoff on the wye was open to the tank flush. When they returned they had a flood and black water coming out the roof vent. S**t happens to the best of us, we tend to get complacent because of all that experience we have.

We were camped at a nice CG and a young couple pull into the site next to us a couple days after we had arrived. I watched discretely as he tried to unhook from the ball and was having trouble so I feigned needing something from my truck and went there and he noticed me outside so he actually asked me for help which I had hoped he would do. I didn't want to embarrass the guy by barging in. He explained he had borrowed the trailer and really didn't have any experience and did not know how the hitch latch worked so I said "are you ready for this?" lifted it up and pulled it back and the ball dropped out of the coupler...that simple. He laughed and we had a good conversation and I told him not to hesitate to ask me if he needed help with anything else. They had a nice stay.