As such, just curious if biostars members would support a policy on the use of AI, and if so, where would it be implemented? Should it be presented alongside other best practices for posting, e.g. use of reprex, or should the policy focus on its use for answers to coding-related (or other) questions? Or, neither/both?
As you indicate, AI in some form or other is here to stay and we can't avoid it in our lives and on biostars.
Main issue I see is the validation of information. If an answer is AI assisted (and code related things fit in this category well) but not tested then unless the original poster comes back and validates the information, it would be way too easy to start accumulating "answers" that may on the surface appear OK but may either not work or at worse lead to incorrect results.
Answers generated solely by plugging a question into an AI tool (BTW this actually works reasonably well) runs the risk of potentially being incorrect, if the person generating the answer does not have domain knowledge to do first pass validation. One could argue that the voting system (and moderators) can manage this but we will need to see how well this works.
Practically, a disclaimer/attribution at the top of a post where (some) content has been generated using AI assistance is needed (which is what a few posters have been doing). Future visitors can then consider that tidbit as they consume the content.