[alien_at_work]

>and then clarify the question title to reflect the problem they need help with.

How many times have you seen that happen? Further that only occurs in an XY situation where the question was wrong. I've been hit by cases where the answer was "don't do that because it's bad". Well, I know that and I know why it's bad but I also know that I have to do it anyway. What now? You couldn't change the question in that case because they asked what they meant, they were just told that they were wrong (and they were).

>I get really miffed when I see someone answering the literal question even when it is clear that the OP have a different problem

And I get just as miffed when they don't because of all the times I get burned by people behaving as you want and then I can't get that same answer answered and have to go through even more pain (it was painful enough to be forced into the situation) to figure it out for myself. I have basically no karma on SO because when I get some I use it to vote down such people.

>Answering both X and Y is fine of course, and probably the preferred.

Here we can agree.

[olavk]

Good point. If they really asked what they want (it wasn't an XY question), I don't think "don't do that because it is bad" should be accepted as an answer, since it isn't, and it doesn't help.

It is the OP which decides what it the accepted answer though, but the community should not upvote unhelpful answers.