I already see really convincing deep fakes on Facebook, etc., it's not an impossible problem anymore, it's just a matter of increasing their quality.
There are always people that claim to be...
Reminds me of photographs asking people if photos were photoshopped or not and people generally guessed wrong about half the time.
The corridor crew noticed something about AI generated pictures. They all seem to have similar lighting and chroma. So they have this 'look' to them (once you see it). That is because the pictures start off as a random noise picture and coalesce into a picture. So the lighting stays the same on just about every pixel.
All the deep fakes I've seen that don't look incredibly weird at first glance essentially re-use clips (like Back To The Future[0]) and they replacement an element, like a face, but the rest of the footage already exists.
If you look closely though, particularly at the mouth of the video I linked, something isn't quite natural about it still.
Same deal with this Taylor Swift fake[1]