Here's one: If you see high disengagement, you know you have to improve as an organizer or that the person should not have been invited.

The context for my point is that we already have authoritarian countries (i.e China, Russia) already using the internet for mass surveillance (and selling the technology to other countries), we have Trump (who has to be considered at least a quasi-authoritarian at this point) purging civil servant who are insufficiently loyal to him.

And these are not power that will have intrinsic knowledge or care about things we may understand intuitively: the error rate of a prediction model, false positives/negatives in classification, the difficulty of producing a reliable model of human emotion, how easy it is to build bias into a ML model, etc.

Agreed, the feature could be used for bad purposes. Does that mean we shouldn't build it? That's a tough question.

You can also ask participants for their feedback.

Yes, but the point of all my suggestions is to make things automatic.

Besides the feedback to the organizer part, there could be all kinds of stats about the meeting, compare to the stats of e.g. a sports game. If you have a pool of sales reps, and you want to help them improve, you can compare the stats: on average you ask 2 questions per call, while the average rep asks 10, etc..

Don't get me wrong, there are a lot of nefarious use cases, but there are definitely positive ones as well.

I can see the use cases, but the nefarious ones kind of obscure this prospect.

Maybe the negatives could be mitigated by doing the automated analysis on the client and asking the users if they want to send the feedback, similarly to how crash reports for software are often done.

Yeah, that might be a good mitigation! It will never be perfect, but that's life ;)

You are absolutely right. I don't want my teachers to know that I am not actively attending the class and doing something else.

Also, even if this feature gets implemented, someone will defeat it easily. ( Example: Teachers ask you to keep your camera feed on during the class? OBS + Virtual Camera )