I'm going to hold them to the same standard no matter if they use crappy sources, plagiarize, or hallucinate on their own. If someone asked, when and if I am in a position where I have to tell them, I would remind them that LLMs prioritize their own confidence over correctness.

LLMs aren't a special case to me. Glue doesn't belong on pizza and you shouldn't eat one rock a day but we've been giving and getting bad advice forever. The person needs to take ownership for the output and getting it right, no matter the source, is their responsibility.