Objectively define 'absurdly high'.

My suggestion of some groups already having deficiency is conjecture based on little hints here and there; more study is needed. My guesses would be: vegetarians, athletes who avoid processed food, ethnicities with a longer history of eating heavily-salted foods, some elderly, some pregnant women.

I suppose that by subjecting the entire population to an enforced low-sodium diet, and seeing who starts suffering from fatigue and early mortality, we'll find out soon enough.