I am not aware of regulations that would prohibit this so long as a licensed driver remains responsible and supervises. If Tesla really has this capability, they could release it with the caveat that the driver must actually be sitting in the driver's seat. They could do that with any of the hypothetical FSD features, once they are available, without waiting for regulatory approval. Tesla loves to show off. If they had anything to show off, they would. Even if only a demo video on a private test arena.