Secko posted an answer to Trying to identify a novel with dragons.
Sevvack responded that it was incorrect. It was a decent, thought out answer which addressed the points in the question, it just wasn't right. Secko deleted the incorrect answer.
Obviously, that's his right to do so, but is it the recommended action?
My thought is that it should not be. While the answer is incorrect, it's still actually useful. The confirmed yes/no can help other people find the correct answer. Not every user can see deleted answers, and don't have the confirmed fact that it is not [Title X] to guide them. Personally, I've upvoted some incorrect answers because they were still well thought out and useful.
We recently discussed Is deleting really wrong answers ok according to the rules?, and though no answer was selected, the general rules Keen mentioned seemed to go largely uncontested. This doesn't seem to fit into any of those rules.