nP - there have been many times when on a business level the impact of the queen not being the queen has been discussed and taken very seriously as it would have resulted in commercial failings. I attended those meetings, I worked on contingencies.
Shortly after the olympic decision was made in 2006 the odds of her abdication that same year were 10 to 1 and would have been significantly higher within the next 7 years especially if you include potential ill health.
I never heard it means it couldn't happen = pig ignorant
So back to why nP is a picnic short of a hamper...
mmxiv