As an extension of the question Should all-Latin questions be permitted?, where the consensus answer appears to be "Yes!", should we define as part of the site policy that any all-Latin questions must include an English translation for the benefit of those not fluent in Latin?
As well: should such English translations be required to encompass the entirety of the Latin post, or merely the key parts?
Personally, I don't think we should require that people include English translations in their all-Latin questions. If we were to get some members of the community who speak better Latin than English, we shouldn't expect them to translate into English.
That said, it should be a policy/guideline that all-Latin questions may have an English translation added to them. That is, OPs should not expect to be able to prevent English translations from being added to their questions. It's ultimately up to the members of the community, then, to add English translations to questions that lack them.
I'm going to repeat the caveat I added in my answer to the other question:
While I think all-Latin questions are fine, they should have an English translation of, at the very least, the main question. The introduction, context, etc. can be in Latin -- and indeed, the context probably will be in Latin anyway -- but the main question should be in English.
This is because Stack Exchange isn't solely for the benefit of the asker -- part of the point is that you can Google "how to python draw image" and get a good question and answer. If we have purely, only Latin questions, then you can't Google for it -- you'd have to be Googling in Latin, which is unlikely.
If you're participating on this site, you probably like language. And if you're studying Latin, you probably really like elegant, economical use of language. And so, if you omitted an English translation in your question, you probably did so deliberately.
Certainly in my first two questions, "Ignis solis propinqui" and "Dies unus"—non primus?, I omitted English advisedly and I would not appreciate someone adding English translations to them. In my third question, Quomodo "cochlear" a "cochlea" est ortum?, I put in a little English crib—just enough to intrigue a reader who doesn't know the words cochlear and cochlea. Adding an English translation to that would be crude, at the least.
Another reason to avoid translating into English when you write Latin is that it's a very bad habit. Translating into your native language actively interferes with learning a foreign language. It's not just a waste of time, it actually messes you up, because you absorb the foreign language as a "virtual layer" on top of your native language rather than as words pointing directly to what they mean and habits of grammar for directly composing thoughts.
Placing the translation conveniently in the next paragraph messes up readers who are trying to learn Latin. When a translation is handy, it's all too easy to let your eye jump to it the instant you experience difficulty understanding the Latin. You learn by getting through the difficulty, not by avoiding it.
Questions not about learning Latin
None of the above should suggest that people should never include English translations, of course. One type of question where an English translation might be especially appropriate is questions about the history of Latin or its connections with other languages: that is, a question not intended to help the asker learn Latin. Many people will use this site with no intention of learning Latin. For them, English translations—indeed, all-English questions with all-English answers—make a lot of sense. It depends on the questioner's intent.
To fix or prevent misunderstanding
Another reason a questioner might want to include an English translation is because the questioner is unsure of his or her clarity in Latin. If you're learning Latin, you're going to make a lot of mistakes, and often say something not just incorrectly but unclearly or even not what you intended to say. In that case, you might provide an English translation to help get your meaning across. This might be especially helpful for questioners who are fluent in neither Latin nor English.
Please, leave this choice to the discretion of the writer. If you'd like an English translation added, then please suggest doing so in a comment rather than editing it in without an invitation.
