Q:

Are "Don't do..." Answers Appropriate?

In Rhys's post on deleting low-value answers, there were many people who stated that downvoted answers have value themselves (for instance this answer by Jim):

Not all downvoted answers should be deleted.
Downvoted answers (especially with comments) can add value. They
basically say "here is one approach to solving your problem. It's not
a good idea; don't do it."
One example is this answer about working for
free. The community
generally agrees that it's a bad idea (shown through the downvotes),
and there is a comment explaining why. Clearly, the idea occurred to
at least one person as a solution to the problem, so it's useful to
keep around something refuting that idea.

Rather than go for deletion of such answers, I'd recommend the first
action be to try to add comments to explain why it's a bad idea. If
that's not a viable option, then deletion may be appropriate.

In the FAQ on Comments on meta.SO comments are clearly intended to be temporary (emphasis mine):

Comments are disposable: unlike posts, there's no revision history, and they can be deleted without warning by their authors, by
moderators, and in response to flags.
...
When should comments be deleted?
Comments are temporary "Post-It" notes left on a question or
answer. You
should not expect them to be around forever: Once a clarification
has been made, an edit added to the post to include new information,
or the issue in the comment is otherwise resolved, it is subject to
deletion. In reality, many obsolete or chatty comments remain
untouched due to the high volume of comments posted, but this does not
mean that they can't or shouldn't be deleted in the future.

Personally I share gnat's take on things:

I believe that it would be better to have an (upvoted) answer that
lays out the idea in the impartial tone and follows up with a
compelling explanation for why it would be bad. If there was such an
answer, I wouldn't mind deletion of the one that gives a pretty shaky
"proof by comment and downvotes"

So the question I want to place to the community is:
Are 'Whatever you do, don't...' Answers Appropriate?
Taking the answer used as an example by David, would it be appropriate to make an answer saying something like:

While it may seem tempting, do not offer to work for free. Working for free may get your foot in the door, but it will cause the employer to value your work at nothing because you're providing it for free. This will hurt your chances to negotiate with the company for a full-time position

This does not answer the question, but it does provide valuable information that is currently hidden in a -7 downvoted answer, and a comment clarifying that the answer is a bad idea. Personally I think that having such an answer would be better than having the downvoted answer as-is, but I wanted to run it by the community first.

A:

There are 27 answers posted on that particular question, and for every new answer added, that's information that gets drowned out by the noise created by the other answers. Even if that noise is valuable, it's still hard to hear over the noise of all of the other valuable information.
Thus, it seems that it may be best to stick to answering the question. While this 27 answer question is an extreme example, if we allow just any information to be posted, we risk taking the focus off the actual answers to the question or even ending up with questions with 10 posts where none of those posts actually answer the question.
To some degree, we see this occasionally on some answers, and I feel like we're already pretty lenient when this occurs, letting some slip under the radar as long as they also address the core question. Officially saying, "post whatever you want", could make it very difficult to moderate a site where the lines may already be a bit subjective and blurry.
What helps mark this particular example answer as a bad answer is the number of down votes. If folks want to learn more, there's a comment posted that adds value. But posting an answer that doesn't answer the question, in a network where Real Questions Have Answers, somehow seems like it could create more problems than it solves. Here's a small portion of the conveyed message from that blog post: 

What kind of questions should I not ask here?
...
we are being asked an open-ended, hypothetical question: “What if __ happened?”
...

A big part of making a great question is in focusing on great answers. If we let answerers do whatever they want and don't moderate them, then the questions may very well take the brunt of the blame for creating poor quality content. By making sure answerers also follow good subjective practices, we help create great questions we may not have otherwise been able to support.  Hope this helps!

