[schoen]

> To avoid this failure mode, you have to provide players incentives to prove that they are human.

This is also more aligned with Turing's original idea.

I agree with you that it's easier for a human to imitate a (bad or inadequate) bot. You could also, for example, run your own copy of Eliza and proxy the conversation to that, or even memorize some of Eliza's rules and literally apply them by hand in your conversation. You would basically always convince people that you're a bot.

Since the human role is understood to be the harder one to implement, having everyone attempt to play it is the most incentive-compatible solution to a contest: it encourages all participants to best demonstrate their abilities instead of concealing them.