Only a matter or time.
"... he is also worried about how GANs can be used maliciously. “It's part of why I chose to focus on more general image modelling rather than faces - it's a lot harder to use images of Dogball for political or unethical purposes than it is to use an image of another person.”
It won't take long for the unethical to start using this sort of technique and whilst experts may be able to detect unreal[1] images it will become harder and harder to do so as the technique improves.
[1] I now try and avoid using the word 'fake' as its use by certain people means it is to me a discredited term.