In any such case, the answer should always be a resounding NO, there is simply no way an IO can find out if you said any such thing in an informal occasion and it simply makes no sense for an IO to ask such a question (assuming the story is true, which I doubt).
Another thing is , though not applicable to most, soem future job may require a polygraph test
that involve certain questions about immigration history. If you once said "I am a citizen" to your
neighbor simply because he always inquire about your visa status and you did not disclose that on N400, later you may find you are in a dilemma when admisnistered that polygraph test