Also I'm pretty certain that it's a mixture of bots and humans by now. I'm using random questions currently and whenever I change them the amount of registered

Also I'm pretty certain that it's a mixture of bots and humans by now. I'm using random questions currently and whenever I change them the amount of registered bots goes down for 1-2 days. Then it slowly comes up again over the week until I think up new questions. So I guess there's probably someone going over unknown questions regularly and adding new answers.