InformedIgnorance
Do you 'know' or believe?
Yet the same can be said of rejecting evolution - because creationism in the broadest sense IS unfalsifiable (the specific psuedo-science often used to justify such as position however often does not share this characteristic, or if it does, then it is not science). In such a situation, rejecting the possibility that creation was the result of some supernatural intervention is indeed not absolutely certain (though it likely remains a rational course). Potentially this rejection could occur as a lack of understanding of different creationism principles - so asking about individuals' levels of awareness about creationism is a valid attempt at understanding potential causes for disagreement.