I met a few underage people via videogames and all ages music venues when I was in my early 20s. Lemme say from experience: it's pretty easy to avoid certain topics, not share or ask for pictures, not seek invites to house parties full of high schoolers. If you're not keeping it above board it's almost guaranteed to be "if you seek it you will find it" territory. You don't accidentally sext a teenager. Or ask them about their sex lives. Or try to see them one on one.
Exactly. I'm getting a bit old to even tolerate hanging out with high schoolers but it's inevitable every now and again, and I assure you that at no point have I accidentally discussed anything sexual with them. It's so easy. For the most part they don't want to talk about that shit with your crusty old ass anyway, and the few who do just need a firm "no, that's entirely inappropriate"