If you can induce ChatGPT to repeat a copyright work, I wonder if that’s definitive proof of copyright infringement. It has no problem reproducing song lyrics

If you can induce ChatGPT to repeat a copyright work, I wonder if that’s definitive proof of copyright infringement. It has no problem reproducing song lyrics for me, which I’m pretty sure are absolutely copyright. Interestingly, it’ll start to reproduce a famous book for me, and then cut off in such a way as to suggest there’s a hard filter to stop it proceeding