No. The Laws of Football and the Laws of Australia are imaginary in the sense you mean, but the Law of Gravity isn't.
Mother Nature's rules are different than ours, stubborn far beyond all reason and not recorded anywhere for our inspection.
Video games are interesting because we make them, yet for the most part some of their rules are like Ma's rules not ours. Watching Mario Maker 2 troll levels, the fact is that even if the player, and the viewer, and even the people at Nintendo who made the game think that Skipsqueak can't jump through that platform, if the game was coded such that it does, it will anyway.
Anyway, I think part of what you're missing is that the people in this story often don't know the rule is imaginary. Sometimes it's an excuse, but sometimes they honestly just assumed there was a reason for things being as they are and never stopped to go find out why. Not everybody has the sort of inquisitive nature that would afford that, some lines of business crush that right out of you.