In my experience it is obvious. Calling people on it also makes them feel embarrassed usually. I put something like “I can just ask an LLM myself if I wanted this output. Please provide your own commentary.” If I were a manager and I had an employee just copy pasting that kind of output, I’d probably wonder if that employee actually contributes anything.

I think this is the way. A certain number of times of “[coworker] wasn’t asked because they only respond with LLMs, so I just ask the LLMs directly. I am not sure what [coworker]’s expertise is anymore, I just don’t consult them” and I suspect coworker may in fact stop responding with LLMs.