It's interesting to me to think about a possible system where people in say roblox can only chat with each other by exchanging physical keys somehow. This way, they would be able to chat with their peers from school etc., without the danger or need for as much supervision. I don't necessarily think this is technologically feasible or something that would be accepted, but I think it's an interesting idea.
* kids play with other kids with same school, worst that can happen is learning some fun words from upper classmate * both teacher and parents can join and play or keep an eye on them * with a bit more it could be segregated to per class /grade server too