You 100% need to test work done by AI, if it's code it needs to pass extensive tests, if it's just a question answered, it needs to be the common conclusion of multiple independent agents. You can trust a single AI as much as a HN or reddit comment, but you can trust a committee of 4 as a real expert.

More generally I think testing AI by using its web search, code execution and ensembling is the missing ingredient to increased usage. We need to define the opposite of AI work - what validates it. This is hard, but once done you can trust the system and it becomes cheaper to change.