Yesterday, a question was posted asking for comments on a fully detailed solution to what was obviously a coursework question. The OP's solution was essentially correct, just overly complicated. The question received three answers, including one from me, which was confined to simplifying and correcting the OP's own solution.
I had, and still have, little doubt as to the suitability of the question for Maths.SE, or the suitability of my own answer.
Today, a different user has posted a request for help with the same question, giving only the most general idea of how [s]he proposes to go about solving it.
This is almost certainly an exact (not even abstract) duplicate of the earlier question. Normally, I would have no hesitation in flagging it as such. But if I do that, then the asker of today's question will thereby be directed to an effortless solution.
I don't know what to do.
Links, as requested in the comments: