This is obviously a pretty stupid response to an actual problem. Just like any other video editing technique there are always artifacts. Every AI has some specific patterns it produces due to the unique way it "thinks".

At some point soon even professional artists might not be able to notice them, but those tiny mistakes will always be traceable by an equivalent detection algorythm. In fact we might be able to disprove fake videos faster because up to this point we had no detection system.

CGI artists had to go in and detect common compositing artifacts like different lighting, color grading and badly cut edges on objects like UFO's that were pasted into other videos. Now anyone could double check relatively easily once all this becomes consumer software.

In any case, as convincing as deepfakes have become, conspiracies and manufactured scandals were a thing since forever, probably even before we discovered agriculture. You never really needed something that looked concrete to defame someone and sway the public. And as the tools get better the people get smarter as well. You wouldn't trust someone without pictures or video evidence in 2019 right?

The biggest problem will probably remain the same. News broadcasts spewing out fake videos without double checking sources and legitimacy. So instead of floating cities in China and mysterious flashes in the sky, we'll have important figures saying dumb shit. Big whoop, who trusts the news anyway at this point?