Because I loathe captcha, I make sure that every time I am presented one I sneak in an incorrect answer just to fuck with the model I'm training for free. Garbage in, garbage out.
Generalizing over the same idea, I believe that whenever you are asked for information about yourself you should volunteer wrong information. Female instead of male, single instead of married etc.
Resistance through differential privacy
Back when recaptcha was catching on there was a 4chan campaign to associate words with "penis". They gathered together, used to successfully brigading polls of a few thousand, and went at it.
Someone asked the recaptcha guys and they said the traffic was so little among the total that it got diluted away. No lasting penis words arose and they lost interest.