You presume opposing counsel isn't using GPT-6 and other, legal-specific models trained on data ChatGPT will never gain access to. Hint: they are.
Regardless of advice quality, legal proceedings aren't free-to-play, and the adversary in question here has bottomless pockets.
Such speculation is just fear mongering and that is exactly what the daft bullies want.
It's kinda-crazy the degree to which legal data--which you need for a fair trial under the law--is locked up by monopolistic brokers.
FFS, we're already at the edge of having to pay to know what the laws even are. [0]
[0] https://www.eff.org/deeplinks/2022/03/pro-codes-act-wolf-she...