I fully understand your concern however this is not an exact science. If it were they wouldn't have given humans ago. Zooinverse has factored inaccuracies into the equation but overall us human do much better than computers with pattern recognition.This is why Galaxy Zoo was such a great success. I think I am guilty of mistaking a regular variable for a exoplanet candidate within the first few I looked out. It just takes a little practice . I have found some cool irregular and regular variables though!!