Why would it be necessary to have a rule to attempt to avoid cheating and encourage participation in Calendar events, and only apply it to two trophies (plus their oppo sex version), i.e. a rule for a tiny group of members,
AFAIK the rule is also applied to veteran (x2) and junior (x2) trophies, and I would have thought Tricycle and Tandem as well but the rule as you highlighted it would seem to suggest otherwise. In other words, 'individual' means 'not team or club'. By that reasoning, AAA would be liable to the 50% rule - but AFAIK it never has been, probably an oversight.
AFIAK it isnt. But if it does or it should then it should also apply to the Fixed Wheel Trophy, in which case I'll be demanding a stewards enquiry for....
...actually I won't, because the winner was far more worthy than I, but still, I'll be carrying a torch for my lost pot till my dying day. I was robbed, robbed I tell you!
And the answer for Bikey Mikeys question is because the rule was dreamt up as a result of one particular rider/incident going for the overall points trophy, and hasty law is bad law.
If only there were an opportunity to discuss this with members of the Board...