Good voice actors can do a whole range of voices, including imitating many different people. The cases where someone got in trouble are where there's misrepresentation. If it goes to court, there's discovery, and if the OpenAI people gave specific instructions to the voice actor to imitate Scarlett Johansson, after denying it, there could be big trouble. We don't know that, but it looks likely given how they first approached her and how they seemed to be going for something like the "Her" film.