I guess I am trying to reflect on what has happened with the centralised platform where kids go on there and predators sent DM of explicit contents and other stuff.  I am curious as a community here, is there a way we can avoid this? I am thinking out loud. 
I am also aware that whether Nostr or any other platforms, you can never gate keep adversary 100%. It will always come down to the parents and to whoever is interacting the tech.  

 Probably not in any reliable way. Soecific applications built on top of nostr might be able to offer a minimal level of protection against that kind of thing, but at the protocol I don't think it's even desirable to try to solve for that. 

 Agreed. Not on protocol level. Also I believe on the thread we have collectively agreed that this comes down to good parenting and the means the children are provided. 🙂