As an Australian experiencing this first hand and considerably older than 16, absolutely nothing has changed. It seems like all the social networks are doing age estimation of accounts and only taking action on those that fail and are detected as underage. The change is otherwise completely invisible if you're an adult user. Obviously I'm only a sample size of 1, but I've not heard of any other adults being adversely…
Nothing has changed for my 15 year old either. It’s business as usual today for her. She says only one of her friends has been challenged by a platform so far, and that was by Snapchat. That friend got another 14 year old friend to pass the facial age detection check on her behalf.
Are you kidding me? So the answer is let's let some random vendors used by said corporation scan her face? This feels like using DNA sequencing to confirm you're tall enough to ride the rollercoaster.