@simon this isn't the whole story.
Some types of fact checking are hard. But ChatGPT's results include things such as made up URLs and citations.
It is much easier to establish the *provenance* of isolated facts like this, than to establish the accuracy of much wider statements.
Further, checking that accuracy has correctly been established is not much easier than establishing accuracy in the first place. Validating provenance claims are correct is even easier than making them correct.