Whether a human or a machine (or a machine that claims to be a human) is doing it, there should be oversight and double or triple checking if the result is used

Whether a human or a machine (or a machine that claims to be a human) is doing it, there should be oversight and double or triple checking if the result is used for anything sensitive. I'd say it's unethical to put the outcome of medical research into the hands of unknown Mechanical Turk workers without any oversight.