We have laws against undisclosed and misleading advertising, because consumers can't make informed purchases otherwise. What makes you think LLMs will have a fundamentally different pattern than everything else?
So far as I've seen, the laws don't apply to AI companies. They do what they want.
And the level of effort required to have these laws applied to false marketers is unrealistic. Unless there is a case of disfigurement or death, it's just caveat emptor.