Quite a few years ago I recall watching a presentation by a leader of a child advocacy organization that was dealing with the various governments in the EU and providing technical guidance to them. They were very close at the time to moving forward with a plan to require video card manufacturers to build things into their firmware to check every single image before it is displayed on screen against a database of known illegal imagery. The crux of the talk from the advocate was that they, child advocacy organizations, spend an awful lot of time and resources fighting against these sorts of high-profile attacks against imagery because it is known to not actually help kids in abusive situations. I keep expecting that sort of policy to re-appear. As technical people, we know that the technical aspects of such a proposal are insane and impractical, but that often doesn't constrain policymakers.