I remember labeling all my sites with PICS ICRA using the header generator. For my SFW sites it was mostly straight forward. For my adult forum it was a pain in the ass. My forum members managed to come up with so many categories that the header at some point should have just said "ALL THE THINGS AND THINGS YOU DID NOT KNOW EXIST" hahaha... I can see why adoption was low. There were a couple of browsers that recognized ICRA PICS for a little while but there were no laws to make it stick.

That's why I am pleased with RTA. Just add one header, done. Most admins and developers could do that in their sleep.