We don't know yet how the Ars article was created, but if it involved prompting an LLM with anything like "pull some quotes from this text based on {criteria}", that is so easy to do correctly in an automated manner; just confirm with boring deterministic code that the provided quote text exists in the original text. Do such tools not already exist?

On the other hand, if it was "here are some sources, write an article about this story in a voice similar to these prior articles", well...

A new-ish feature of modern browsers is the ability to link directly to a chunk of text within a document; that text can even be optionally highlighted on page load to make it obvious. You could configure the LLM to output those text anchor links directly, making it possible to verify the quotes (and their context!) just by clicking on the links provided.