One of the reasons why I love this site is because of the hard boundary that prevents adults from initiating friend requests to people who are underage. I think that is an absolutely fantastic setting that every single social media site should have.
I think it would be awesome to take it a step further as well, and add an optional toggle for 18+ accounts that don't feel comfortable having minors view their page / initiate friend requests. Often times, even a nice flashy "MDNI" tag on a page ends up being overlooked.
So, I think it would be cool to have basically the same system in place for adult users as well, just have it be an optional toggle, since there are plenty of adults who feel totally safe in being that Good Adult Role-model!