This is consistently the case too, not just in financial systems. Even language, which is loosely structured and something we get 'wrong' a lot on a day to day

This is consistently the case too, not just in financial systems. Even language, which is loosely structured and something we get 'wrong' a lot on a day to day basis, is better for that reason - strictness just doesn't fit into the world of human beings. We're much better at using context to make case by case calls - a rigorous, inflexible system is playing against our greatest strengths.