While I agree that is a good rule of thumb, it's not always possible to see both the solution AND the flaw.
If you see both, say both and take your time. But if someone says "Let's shoot ourselves in the foot" and "Let's not, that wouldn't help" is all you got, it's all you got.
"Lets not" or "that would not help" is part of a alternate solution. If An Idea is so dumb pointing out that is the wrong direction is a "solution" to go another direction.
While I agree that is a good rule of thumb, it's not always possible to see both the solution AND the flaw.
If you see both, say both and take your time. But if someone says "Let's shoot ourselves in the foot" and "Let's not, that wouldn't help" is all you got, it's all you got.
"Lets not" or "that would not help" is part of a alternate solution. If An Idea is so dumb pointing out that is the wrong direction is a "solution" to go another direction.