Best "shut em down" moment?

Usually, my wife and I do just fine backing our 5th wheel into a site. Her basic job is to make sure I don’t back into something. But on this day, at this particular huge campground (600 plus sites) in south Texas, I was told to follow the camp host to my assigned site and he would assist me backing in. I followed him around in his golf cart down and around some narrow streets until he stopped. He pointed to a site behind me and went back and stood where the driver’s side rear corner of my trailer would end up. I could see him clearly in my mirror, so watching his hand motions waving me back I was slowly backing in perfectly, and then, thank goodness, a helpful person from 50 yards down the street yelled “STOP”! The front right corner of my truck was about two inches away from running into the side of a brand new shiny red Ford truck. Lucky for us, one of those well-meaning persons saved us from a lot of grief.