Was reading a book in the back of the boat while moored in central Brum a few years ago. The wife got off to do some shopping, and a few minutes later I felt the boat move.
I looked up front, expecting to find that SWMBO had forgotten her purse or something, but not a bit of it. Several people were busy making themselves comfortable to pose for a photo in my well deck. They legged it quickly when I invited them to vacate the area in short, jerky movements.
SWMBO later told me that she had seen the group standing there looking at the boat. They'd obviously waited until she was out of sight and then hopped onboard. Bloody cheek.