Hey both of these are covered on the FAQ

proxy to bypass blocked sites was common knowledge

It’s not a technological block, the social media sites will rely on a variety of signals, for example if you sign up for a facebook account in USA, but take a selfie geolocating you in australia and image scan picks up that you might be under 16, you’ll still get pinged for id check

amongst the smarter kids

They are targeting all under 16’s, and this is mentioned as well, even if 10% of kids get around the ban somehow, the fact that 90% don’t removes a huge part of the social in social network