I have seen that happen, and worse ! I watched a fellow try to launch his boat, and kept backing into the water, with the boat still lashed down to the trailer. The boat sank, and he couldn't get the truck back out with all the weight of the water in the boat. He had the launching area tied up for the rest of the day, until a tow truck pulled the truck and trailer with boat out of the river.
No, I didn't have a camera with me at the time.... It seems that you seldom do...
Bill