Sure, there are legitimate but opposing interests here. The solution doesn't have to be technical though. The key part is making sure that the copyright owners

Sure, there are legitimate but opposing interests here. The solution doesn't have to be technical though. The key part is making sure that the copyright owners still have some recourse, but one that isn't punitive for unknowing infringement. For example, make it legally impossible to impose punitive penalties for unknowing infringement without commercial interest, but make it possible for the rights owner to demand the relevant material be removed etc. Also keep in mind that the Mario examples from the article are perhaps not the best guide here. Mario is sufficiently pervasive in our culture that you can't reasonably claim unknowing infringement. It's the somewhat more obscure cases that I'd be worried about.