This kind of lunacy seems to me like a way for governments to infringe on freedoms more and more.
"Oh... But it's for the CHILDREN! You don't hate CHILDREN? DO YOU?"
It's a kind of sneaky emotional blackmail and it's disingenuine. Of course nobody "hates children", but imposing insane legislation doesn't fix the real problem.
A similar law was passed in Canada a while back -- If you are Canadian, and you go off on pedophilic sex tours outside of Canada, you can be charged IN CANADA upon your return. Now, it's a great idea to protect kids, but infringing on another nation's sovereignty is a bad path to go down.
These things seem like very dangerous slippery slopes that lead to very... very dark places.
To be honest, I believe that these sorts of things are the exact reason for the right to bear arms in the USA. At some point, governments overstep their bounds and stray into those dark places where violence becomes the only saviour. History is full of examples. Today is no different.
Freedom has always been paid for and stained by blood, and most likely always will be.
Rant aside, at some point in the future there may be technologies that make this sort of thing possible. However, we don't have that kind of technology at the moment. Years ago there were attempts to do image recognition for this sort of thing, but they all failed. It's just too intense of an operation to do. Much more CPU and computer resources are needed for this to become remotely feasible.
Analagously, the legislation is like saying, "If you see someone in distress, you MUST help/save them." This is just pure insanity. Ok - you see someone screaming on the 10th floor of a burning building... We see the problem then. You're effectively being asked to do something that you simply CANNOT do. It's just not possible.