Got this idea from games where you have to answer questions wrongly. Which questions are always answered correctly? I can only think of negatives of questions which have no answer, like “what is NOT the answer to world peace?”. Are there more creative questions out there?
“Are you alive?”, “can you hear me?”, etc. can all be answered incorrectly, so they don’t work.
Perhaps a Smullyan-esque self-referential question would work, like “Given that any answer other than ‘yes’ will be taken to mean ‘no’, is your answer to this question ‘yes’?”