I think a manually-added annotation of this sort, with a link to the "why ask a rabbi" question as Charles suggestedsuggested, would be helpful. I wouldn't want to see it be automatic; per guidance I've seen from Shog9 (community manager), annotations should be rare or they lose their oomph. So we should save it for questions that are particularly practical in nature, not all questions tagged halacha (221 at this writing).
replaced http://meta.judaism.stackexchange.com/ with https://judaism.meta.stackexchange.com/