But what about observer effects? People act differently when recorded, and rarely do we catch humans acting natural when knowingly observed (some of the early 24h/day Twitch streamers come to mind). And what happens once trials are done? How would people feel about their actions becoming part of a technology potentially able to replace them?

Even when this barrier can be overcome (i.e. people become accustomed to wearing these devices), I worry about the opt-in nature of it. We've yet to see a disruptive technology adhering to this principle through-and-through, and if current learning efforts are anything to go by, training data is not something companies want to willingly let go or lose out on.

Taken both, this path has the potential to be quite coercive if no strong guarantees or safeties can be upheld, especially if early exciting trials generate an interest-boom similar to the one we're seeing right now in the LM-space.