> I can't imagine fooling any (meaning all, I assume) humans; there is too much ambiguity in the signal.

I think you've inverted the expectation here. What I was saying is a machine passes if you can't find anyone in the world who can distinguish between it and an actual human. Meaning that if the "world's smartest person" can distinguish between it and an actual human, it fails, even if it can fool everyone else.

A machine can pass the test by deliberately feigning to be a human with limited communication capabilities (ex: I think we can simulate 2 month old baby talking via text). But then all you've shown is that your machine is as capable of thought as a 2 month old baby, which probably isn't the bar that you're trying to reach.