I can visualize it to some extent. Shortly after completing my PPL, my neighbour took me along a few times to fly the company Aztec with him. Then the company bought a Cheyenne. With about 150 hours total time, I was allowed to fly a Cheyenne from the left seat for a positioning flight - I think just 'cause it amused him. A steep, fast learning curve on that flight!
That said, I would agree that such a situation is out of the norm, and difficult to plan for...
I now return the thread to the Scots and the English, to compete in the use of the language of the English....