It depends on the question.
Stack Overflow is not in the business of policing users' actions with regard to other entities like potential employers, so questions shouldn't be flagged for that reason.
However, in the case of that question, it falls into the category of what not to ask:
You should only ask practical, answerable questions based on actual problems that you face. [Emphasis added.]
That question is not an actual problem, it's a purposely highly contrived problem.
Moreover, it also falls into the category of Too Localized:
This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet.
Hopefully your interview questions will never reach the point of being of interest to the internet at large.
All that said, some interview questions are fine. If you ask questions like "Sorting 1 million 8-digit numbers in 1MB of RAM," on your questionnaire that's a perfectly legitimate question for both an interview and Stack Overflow and should not be removed.