Well, AI does make errors, and never says "I don't know". That is also true of Wikipedia though. I've seen much improvement in accuracy from 3.5 to 4.5. Hallucinations can often be hashed out by a dialogue.
Wikipedia has multiple ways it tells you it doesn't know or it doesn't know for certain. Tags such as clarify, explain, confusing (all of which expand into phrases such as clarification needed etc) are abundant, and if an article doesn't meet the bar for the standard, it's either clearly annotated at the top of the article or the article is removed altogether.