In my experience, it's unambiguously worse to produce wrong answers confidently than to return no answers, although I expect confidence men (also known as "con men") have a different opinion on this.

Hard code a preface of “My best guess is, and I could be wrong:”?

Show both the SQL query and the results and politely request that the user double check the work? Show multiple generated responses from different seeds?

This is fantastic. This is what we do on our platform. + Copy and keep what worked and what did not so you can fine tune :)

Exactly my experience trying to get GPT-3 to produce SQLITE queries. Anything with a CTE, it gets hopelessly wrong. I was super excited to show off this to my team and after one too many false results I just quietly swept this idea under the rug.