NRKbeta, the tech vertical of the Norwegian public broadcaster NRK, actually did the manual version of this a few years back [0-1], but found it hard to conclude with success or failure based on the evidence they gathered.

[0]: https://nrkbeta.no/2017/08/10/with-a-quiz-to-comment-readers...

[1]: https://www.niemanlab.org/2017/03/this-site-is-taking-the-ed...