Since some people are still unsure of the technology behind the McHitch and how it all works (particularly how the McHitch DOESN'T swivel on the pin), here we have provided a cutaway showing what's really going on.
We like to think these pictures speak for themselves; an off the shelf ball coupling and a production model 3.5 tonne electric brake McHitch were cutaway (the parts cut away are highlighted in red).
Note how much(or how little) is actually stopping the ball coupling coming off the towball; note how much slop there is with the ball coupling; note how tight the tolerances are with the McHitch (without compromising ease of attachment); note the three seperate security devices ensuring the McHitch can't come adrift from the tow pin.