Nobody except OpenAI knows whether or not OpenAI trained on their data. So the burden remains on OpenAI here.
That is an absurd and entirely untenable position that breaks with approximately all western conventions.
Only the CIA knows whether or not they're actively covering up reptilian space aliens exerting control over the US government. Therefore the burden of proof remains on the CIA to prove that they are not actively participating in such a scheme.
Incorrect, Buckmaster and Alpöge can comment if they had the ChatGPT "Improve the model for everyone" setting enabled or disabled.
If it was enabled, then their work was included in the training dataset.