Parent accounts require an ID [1].

Kids don't have ID. How would that work?

I think one approach would be that all communication features could be opt in, by parents. but, that doesn't actually "solve" anything, since predators just make child accounts for themselves, and opt in.

sounds like your solution would have to be "no children communicate on the internet".

[1] https://en.help.roblox.com/hc/en-us/articles/4407282410644-I...