FWIW, this line of reasoning comes up pretty regularly (especially in response to that survey question), so if the surveyors fail to realize the associated difficulties, it's not through failure to have it pointed out. I suspect they realize it just fine.

For my own part, I just skip questions that I don't know how to answer and move on.

Incidentally, LW has a preferred local understanding of "supernatural," which derives from this post. That's not to say everyone here thinks it's a good definition -- I don't, for example -- but it's probably the best Schelling point to use when a shared understanding is important.