I found at least one example[0] of authors claiming the reason for the hallucination was exactly this. That said, I do think for this kind of use, authors should go to the effort of verifying the correctness of the output. I also tend to agree with others who have commented that while a hallucinated citation or two may not be particularly egregious, it does raise concerns about what other errors may have been missed.
[0] https://openreview.net/forum?id=IiEtQPGVyV¬eId=W66rrM5XPk