What should we do with answers only saying what not to do and advising readers to follow another answer instead

Question

In this answer the user is sharing his experience of what not to do and says to follow the existing accepted answer.

IMHO this is a partial answer at best and not an answer at worst, but the OP has a point that it might help someone trying to do the same as he did in the future, so taking this to meta.

Should we keep this partial (non-)answer or delete?

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P.S. I'm not talking about questions where the only answer is:

Please, don't do this!

Just questions where there is an answer, but a don't do this is posted.

Answer 1

I agree with dessert's answer that this type of information is probably usually best incorporated into a more complete answer, probably the answer it is recommending. It would, I think, be silly if questions accumulated answers warning against every possible wrong approach to a problem. It would only take a great imagination to come up with all kinds of bad ideas :)

Still, I don't think what not to do answers should always necessarily be discouraged or deleted. It is certainly acceptable for multiple answers to be posted to a question each addressing different aspects of the question and/or covering different approaches to the question or problem. These answers can and often should refer to each other. There is nothing wrong with an answer that says something like

The [answer by user](link to answer) gives the best approach to voozhing your wobflocker and I recommend following it. In this answer, I want to explain some other highly relevant things, [...]

Some such highly relevant things might occasionally be common pitfalls. One valid reason for addressing these in an answer would be that the OP has mentioned in the question that they are thinking of following some bad plan. We should definitely make sure that the badness of that plan is explained somewhere.

While it's often great to simply contribute an edit to someone else's answer to make it more complete, (and that's probably the right approach when you only want to mention a possible mistake that only takes a sentence or two to describe) there are plenty of occasions where what you want to add just doesn't fit into an existing answer, or where you feel that you need the answer to be your own so that you can maintain it properly and cover everything you want to mention thoroughly.

The best questions usually have multiple valid and relevant answers, and we shouldn't discourage people from answering with different perspectives.

Answer 2

No, we should not allow this as an answer.

If the information is important enough to keep it, it should be added to the solution answer as either a comment or – much better! – an edit. This should of course not be overly long, I consider it just an addendum. In this particular case a single sentence with the warning is enough, e.g.:

Do not edit /etc/lsb-release to change the OS name, this breaks software relying on this information such as software-center.

Answer 3

A non-answer?

You could argue it is a valid answer, since it attempts to point OP in the right direction, although it is in the negative sense. I'd leave it where it is.

Just like a question like:

"How do I..."

could have a (valid) answer:

"You can't, because...."

although it is not answering the question, as OP asked it. Similarly, I don't believe saying explicitly what not to do, with a good reasoning, is a non-answer. In both cases, it is a useful contribution to what OP asked for.

A good argument to leave it as a stand-alone answer could then be to make sure it is read. Better that than to bury it somewhere in another answer. That is especially the case when incorrect or even dangerous/harmful answers exist on the internet.