I am now looking for a "non-sucking" way to identify humans without distracting ordinary users too much.
I decided to put this to an extra thread, as it is a different subject than scripted chat.
What was said so far:
I could use common words displayed on a screen every two minutes or so, and only pay out every 5 minutes. No payout if the captchas are not identified correctly. I have no idea yet how to make the user validate the captcha, since chatting would defeat the purpose (if multiple agents use the machine, the chatbot could just listen on the channel to get it).
Hmm, make it so they have to touch the machine every few minutes when prompted, preferably touching a colour coded button ?
Any further ideas?