Client code can always be bypassed. If were talking hiding content from dirty relays for the majority of users yeah I this would be pretty useful! In the case of aedile, we maybe could add a toolkit/utility that can filter this content if it's fetched from a dirty relay. I don't recommend opinionated libraries so I think it should be left up to the application builder to decide how they want to handle this because csam stuff casts a wide net that is constantly expanding. 

I've been thinking of the architecture more and how we might be able to implement a "pluggable" event filtering system which I think would be pretty neat, kind of similar to how Grain's kind handlers are implemented.