I guess. Meta claims these will know when the LED is blocked, but that's probably circumventable as well. And little hidden cameras also already exist, and people filming in public is already a thing, so I don't really see how this specific product will change things in any significant way.
This specific product is backed by one of the largest corporations on the planet led by an absolute ruler who is at best amoral if not absolutely immoral, and has a long, long, long, long, long history of violating privacy, breaking promises regarding privacy,[1] and of refusing to accept responsibility of the consequences arising from doing so.
There are other amoral and immoral players out there, certainly. Few have Facebook's resources, however.
"The trust me, dumb fucks" still seems to be his guiding compass.
As for hidden cameras and unauthorised video: regulation is required. I'd suggest attacking the trade, transfer, and publishing of such video, as well as a strong right-to-privacy legislation. I'm not holding my breath, however.
Requiring The Rest of The World have 100% situational awareness to look for the glowing specs is also frankly ridiculous.