They may understand what is meant.Interesting. I realise that I am biased by my background and 'the world I work in', but I would have thought that the majority of 'ordinary persons' do (whether they realise it or not) understand, accept and often use the statistical meaning of "probability" - i.e. they do understand (and use) the concept of 'low probability'. Because of the dictionary definitions, you appear to believe that a "probability" always has to relate to a fairly high (statistical) probability - is that the case?
Whether they think about the actual meaning of the words is an entirely different matter.
Reasonably low is fine. It is probable someone in Britain will be killed by lightning this year.As above, I would think that the majority of the general public do understand the (essentially statistical) concept of a "low probability", which you don't seem to regard as a valid concept.
However, if something is vanishingly small or non-existent then it is not probable (likely).
There will probably be a major earthquake in London tomorrow is not correct.
I've accepted that the use of probability when working on probability theory is not going to be altered to possibility below a threshold but that does not mean it is the correct use by definition.I'm not quite sure what your point is. As I have said, statistical probability can be zero (or low, or extremely low), albeit usually in relation to silly theoretical cases. For example, the (statistical) probability of a dead person being alive is zero.
Not in this case.Well, if you were using 'proper grammar', you would probably say "my", rather than "me"
I did mean in a situation where it is not going to happen - substitute Sun for Moon.Notwithstanding that, I agree with you, but not for the reason you are presumably thinking of. Although there are situations in which it would be extremely improbable (e.g. if the person was an incapacitated 90 year-old), I suppose one can never say that it is totally impossible that any given person will ever go to the moon - so, in 'my' language, I would be happy for them to say that "The probability of me [my!] going to The Moon is incredibly small" - but you do not accept the concept of incredibly small (or even just small) probabilities.