SafetyNet could be made up of willing masternodes that have sophisticated child locks that can't be tampered with by the child.
Nothing is childproof.
More seriously, I am absolutely against any kind of content filtering on both technical, legal and moral grounds. And that's a lot of boths!
Techinical: everything should be encrypted, the system shouldn't be able to determine the content anyway.
Legal: when you allow some things but not others (or try to) you lose your common carrier status and become legally responsible for said content.
Moral: fuck censorship.
I know censorship is terrible. I'm just thinking since pornography already has its place it would not be censured only channeled to a specific spot, the old internet. If porn was relegated to the old internet there would be no reason to have it on the new one because if people were really concerned about hiding what porno they watch they can buy a dvd or go through the original Tor on the old internet if they want to. This way no one can see what they are doing and if they are concerned about compromising their IP adresse with relation to pornography irrelevant of content they are surely into something wrong. (maybe politics
) and what is the government going to do or say, they are watching some kind of porn? This would silence any claims of relation between anonymity on the web and child pornography once and for all. We need to eventually work to take that stick away from them might as well do it now. 
BTW, I LOVE THIS!