If somebody asks a question on Stackoverflow, it is unlikely that a human who does not know the answer will take time out of their day to completely fabricate a plausible sounding answer.
At least it used to be true.
Have you ever heard of Dunning Kruger effect?
There's a reason why there are upvotes, solution and third party edit system in StackOverflow - people will spend time to write their "hallucinations" very confidently.
People are confidently incorrect all the time. It is very likely that people will make up plausible sounding answers on StackOverflow.
You and I have both taken time out of our days to write plausible sounding answers that are essentially opposing hallucinations.