What happens when moroons travel to fast!

I'm still not 100% convinced that hire company's tell their hirer's to slow down. A Shakespeare boat out of Mercia came passed us moored boats at what seemed like full throttle!! The owners of this narrow boat had only put in pins and then gone off for a pint or two in the pub. Consequently the pins were pulled by the manic speed of the hirer's boat and this one ended up across the cut. It was eventually pulled back in by the chap in the boat behind us and Ian made the boat secure by putting the pins through the cladding and tying the ropes to it.( That will make the owners think on their return!!).