Torquing tire stud by hand

Working on so many different vehicles at an auto charity here in the mid-west, the concern I have using a torque wrench on lugs is related to corrosion/rust. A torque wrench is great when all the lugs spin on freely and all mating surfaces are clean, but add significant corrosion and the torque cannot be trusted. Rust on the mating surfaces of the rotors-to-wheels and lugs-to-wheels all play a role in lugs not remaining tight. The corrosion crumbles after the fact and then you have under-torqued lugs. That is why they suggest to re-check the lugs after a while and why I personally add a little extra torque. The under-resourced people I help rarely check tire pressure and oil level. Asking them to check lug torque isn't going to happen.