You obviously misunderstand. The point of the watchman is they are responsible for telling others. If they fail to warn other when they know, any blood that falls is on their hands, if someone was warned and they fail to act, the fault is not on the watchman but the person warned.

And your response tells me you have read very little in the Bible aside from ignorantly quoting scripture to prove to someone how wrong the Bible is or inappropriate you feel it is.