I don’t think your question is unfair*. They can check and so can Buckmaster. If he didn’t opt out, there’s a good chance his data was used for training. I believe this to be the case myself. What I’m more skeptical about is the purported impact of this data on the model’s behavior.
Yeah, I'm just curious about the setting. It's just weird to me that this wasn't disclosed by either party while the accusations were being made, that's all. Even if it was used in the training data, I don't believe it had that much of an impact myself, since the solutions are quite different.