Even Mythos can hallucinate[1] with a codebase to analyze. The argument I often see is that humans are fallible, too, but the issues we're seeing in this topic are about those who should know better—including in senior positions—heeding LLM responses/advice over human and concerningly not actually thinking about things at all. Ie: they're not being treated by many as just useful tools/tentative feedback but as authoritative answers/solutions.
There still needs to be critical thinking involved on the human side, even if there's a high rate of accuracy in certain dimensions.
That's a bad example: it did not hallucinate about the codebase (which it had access to), but about a rule outside the codebase (which is not in the context, I assume). Yeah, missing requirements can cause it to rely on things it thinks are true. Same as humans do all the time when they lack context.
There still needs to be critical thinking involved on the human side, even if there's a high rate of accuracy in certain dimensions.
[1] https://news.ycombinator.com/item?id=48434824