Consider three examples currently visible on the active questions page:
a. How can I familiarize elementary school students with infinities larger than $\aleph_0$?
c. Advice on starting a math circle in a small rural University town
I use these questions as references, but I have no thoughts to share here about my own personal beliefs on them specifically. Instead, what I wish to ask is the following:
Question: If an MESE user posts a site-appropriate question about how to achieve something, then is it appropriate to respond with a justified-post about why one believes doing this particular thing is inadvisable?
On the one hand, stating why not for a how to post simply does not constitute an answer to the question; on the other hand, I am sure that we do not want to promote poor practices in mathematics education (in fact, I would go so far as to say such behavior is antithetical to the goal of this site).
My view is that the latter point is more important than the former, so that a response of this nature ("don't do XYZ, because ABC") would be both appropriate and desirable. But I readily concede that I may be missing subtleties in this matter, and have tagged this meta-question with discussion in the hope that it can be discussed.
More generally: What is the appropriate response to a how to XYZ question when one feels XYZ is a bad idea? Some options (which I neither declare to be "good" nor complete) are:
Down-voting the post, and adding a comment explaining why.
Adding a comment stating briefly why one feels this is a bad idea, and asking the OP for further justification as to why such a practice would be advisable.
Posting an answer that says XYZ is a bad idea because of reasons ABC.
Posting an answer that attempts to explain the how to, but including a disclaimer as to why this might be inadvisable in practice.
Only posting if one has something concrete with regard to how XYZ could actually be achieved.
"Your goal seems to involve PQR, which I prefer to XYZ, and you may get to PQR by trying ABC."
Discussion of related questions would be welcomed as well, e.g., surrounding votes/comments on others' answers for posts of this ilk.
Expanding momentarily on my comment above:
I am sure that we do not want to promote poor practices in mathematics education (in fact, I would go so far as to say such behavior is antithetical to the goal of this site).
I think that this must not be applied only to questions, but also to answers. In particular, I mention this answer (cf. my comments there) as an example in which I would argue it is not only enough to down-vote the post, but that the post should be removed (I flagged it for deletion, but the moderator opted instead to comment). From my perspective, an answer that promotes poor practices pedagogically may be commented on, questioned, even down-voted if necessary; but one that suggests e.g. sexual misconduct has no place on a site for educators of any sort.
Image anonymized and preserved for posterity: