If this is not the case you should not be sending it to public repos for review at all. It is rude and insulting to expect the people maintaining these repos to review code that nobody bothered to read.
The difference here is that the generator is a non-deterministic LLM and you can't reason about its output the same way.
As for LLM code assistants, I don't really view them as traditional code generation tools in the first place, as in practice they more resemble something in between autocomplete and delegating to a junior programmer.
As for attribution, I view it more or less the same way as "dictated but not read" in written correspondance, i.e., an disclaimer for errors in the code, which may be considered rude in some contexts, and a perfectly acceptable and useful annotation in others.
No. I don't want to test and pick through your shitty LLM generated code. If I wanted the entire code base to be junk, it'd say so in the readme.