[riffraff]

I would guess something akin to existing copyright/branding rules?

Something like "can an unknowing person genuinely confuse the copy with the original, and did the person who produce the copy did it to exploit such confusion".

[bawolff]

Is that the existing copyright rule? It might be the existing trademark rule, but i don't think that is the existing copyright rule.

Arguably from a copyright perspective deepfakes might be derrivitive works of the used source material, but that is generally owned by the photographer not the model.

Probably personality rights would be the way to go here, rather than trademark or copyright.

IANAL.