I don't doubt that they found some evidence of AI use. I'm just skeptical that the amount and strength of evidence has anything to do with their making this statement.
I've been thinking about why the AI companies are making so much use of fear based marketing. And I'm wonder if it isn't just naked Machiavellianism at work.
For a long time tech companies were forced to compete for power by being the most loved (or at least not the most hated). But now they've found an avenue to cultivate fear.