A LLM (or doctor) recommending that I take a rock can't hurt me. Screwing up in more reasonable sounding ways is much more dangerous.

Actually, swallowing a rock will almost certainly cause problems. Telling your state medical board that your doctor told you to take a rock will have a wildly different outcome than telling a judge that you swallowed one because ChatGPT told you to do so.

Unless the judge has you examined and found to be incompetent, they're most likely to just tell you that you're an idiot and throw out the case.