The age of posting on Facebook under your real name with privacy settings public is long gone because of the numerous obvious risks.
But just being seen in a small segment of a YouTube video with no name is a pretty minor risk.
According to my 18 year old niece, FB is just for old people anyway. (Thank god I never really used it). They still use Instagram, though.
Privacy concerns .. are little in general. Hard to be popular, when you avoid the mainstream plattforms. And yes, private groups are on the rise everywhere.
It might become a slightly larger risk when image processing and face recognition get cheap enough that anyone can search to find every video/livestream/photo containing your face.
- the victim knows they are fake, which provides some emotional distance (similar to when actors choose to use prostetics or doubles for a nude scene: the viewer doesn't know but the actor still feels more comfortable)
- most of them are bad enough that the discerning eye can spot it as an AI image (many chronically online people are scarily good at that)
- they can be proven to be fake because they are just an imagined version of your body ('look, I have a tatoo/mole/scar/blemish here that isn't in the nude, it's obviously fake')
AI nudes are still pretty bad, but services that turn up nude images of you by indexing the internet with face-detection are way worse
I'm also aware there are probably a number of guys on this site who work in that space so just as a message to you if you're reading: You suck.
It's given rise to a much richer form of social media and "personal brand" building when done well, IMO. Although I have noticed the tide starting to turn, with the amount of us-vs-them sentiment all over the internet lately.
Honestly, if I was a kid just discovering social media today, I'd be extremely guarded too.