Well, let’s face it, we do now live in a world where that is a distinct possibility. Imagine it being used against someone we support? Even if it was “proven” fake people would still believe it.  On the plus side I imagine the deepfaker themselves would be guilty of possession/trafficking/production of such videos by virtue of the things necessary to have made it in the first place, so we can go after them for that, plus a new take on libel or something. I don’t think we have any hope of banning this kind of technology (especially since it’s something we spend hundreds of millions a year on in academic grants and such), but we do need to get legislative control over the ramifications of it.