I've copied-pasted comments I made on HN from like 2020 and had it tell me it's "100% AI". I've seen examples where the services claim "100% AI" because there was no normal dashes, only em-dashes. Even have a recent example from HN itself: https://news.ycombinator.com/item?id=48165690
> This reads very AI. Pangram [0] agrees [1]. [0] Not perfect, but I think as good evidence as any: https://arxiv.org/pdf/2501.15654 [1] https://www.pangram.com/history/44cd07d3-ba94-4331-8c7f-a626...
Said Pangram report literally citing the single evidence of em-dashes...
Throughout them being available I've tried them every now and then, both with AI generated trash and my own pre-LLM writings, and had about 0% success in getting them to accurately report what it actually is. Maybe my writing style and what specific LLM you use matters a lot, I'm sure these platform's training data is mostly from the mainstream models so as soon as you use anything else, they'll get trivially lost. But again, I don't have any evidence and proof behind this, based only on when I've tried to evaluate them myself in the past.