Other than the obvious but of calculating "miss" as a kid, what about calculating the weight based on age and sex? That's potentially inaccurate too... Imagine

Other than the obvious but of calculating "miss" as a kid, what about calculating the weight based on age and sex? That's potentially inaccurate too... Imagine if there's a bodybuilding convention and a plane gets half booked by bodybuilders, they will be calculated with the average weight of an adult but they weight more than the double