Now that I have a little more time to search around, I easily found this study, published March 31st this year, so not quite 3 months ago:

https://arxiv.org/abs/2503.23674

I only skimmed it, but I don't see anything clearly wrong about it. According to their results, GPT-4.5 with what they term a "persona" prompt does in fact pass a standard that seems to me at least a little harder than what you said - actively picks the AI as the human, which seems stricter to me than being "unable to distinguish".

It is a little surprising to me that only that one LLM actually "passed" their test, versus several others performing somewhat worse. Though it's also not clear exactly how long ago the actual tests were done - this stuff moves super fast.

I'll admit that I was not familiar with the strong version of it. But I am still surprised that nobody has done that. Has nobody even seriously attempted to see how LLMS do at that? Now I might just have to check for myself.

I would have presumed it would be a cake walk. Depending of course on exactly how we define "average interrogator". I would think if we gave a LLM enough pre-prepping to pretend it was a human, and the interrogator was not particularly familiar with ways of "jailbreaking" LLMs, they could pass the test.

“Enough pre-prepping” does a lot of heavy lifting there.

It isn't a fair test at this point though because the stupidity of the average human would be too obvious.