And bad solutions can still "solve" problems with horrible trade-offs, so instead of searching again for a better solution people may just employ the worse one unaware of the better possibilities, consequences be damned.
For instance, if it's a semi-vague question just pointing in the direction of a solution, then I think it's fair to question the motivation of the poster.
But if it's a very precise question about how to accomplish something specific, I think the burden should be on the person answering to add the clause: "you can do X, but its generally not considered a good idea because Y".
Honestly if you can't answer the original question, I get the impression you're just trying to be a smarty-pants and show off some domain knowledge you have which is related to the task at hand.
Listing all of the things you don't want to do would not only take up more words and effort than the question about what you do want to do, but is hopeless. Somebody who doesn't know the answer to your question but still wants to comment will find something that you were unaware you didn't want to do.
It's better just to answer questions directly, and then when somebody uses that solution and it doesn't get them closer to the solution to their real problem, they'll ask a better question.