> You're making a classic a burden-of-proof fallacy

This is incorrect, and you invoke Russell's teapot incorrectly too.

It would only apply if the accusation rested solely on the fact that neither of us have evidence against the accusation.

But that's not the case. First, we know that there could be proof, it's just apparently burdensome and expensive to produce. At that point you're not in fallacy land anymore, you just need a way to balance the cost required of someone to prove the accusations against them false.

Second, we have an arguably plausible mechanism of action that OpenAI does not dispute is possible.

This isn't a legal dispute, so no one is going to force OpenAI to do anything here, but it's not unreasonable (and certainly not fallacious) to suggest that Buckmaster's suggestions are plausible enough it's up to OpenAI to stand behind their denial.