> I am willing to wager the overwhelming majority of extant flagrant errors are due to humans making shit up

In general, I agree, but I wouldn't want to ascribe malfeasance ("making shit up") as the dominant problem.

I've seen two types of problems with references.

1. The reference is dead, which means I can't verify or refute the statement in the Wikipedia article. If I see that, I simply remove both the assertion and the reference from the wiki article.

2. The reference is live, but it almost confirms the statement in the wikipedia article, but whoever put it there over-interpreted the information in the reference. In that case, I correct the statement in the article, but I keep the ref.

Those are the two types of reference errors that I've come across.

And, yes, I've come across these types of errors long before LLMs.