Make it more clear that partially answering a question is frowned upon

Question

This is generally discouraged, especially in more recent months, but the only real mention I've seen of it was on my answer to this question. I feel that if this is a rule (or at least a strong suggestion), then it should be more well-displayed. Perhaps add something to the rules, or make a PSA in META?

Comments

This is one of several things that I would push to be included in the rules (stay tuned). For now, I suppose this thread gives publicity to the idea.