"The more precisely you specify a requirement, the less room you leave for judgment.
The hardest failures to prevent are the ones that sound rational. In a request to bypass a guardrail “just this once”, the decision is not crazy; it is only incomplete.
In a request to bypass a guardrail “just this once”, you will feel pressure to keep the conversation optimistic. Optimism is expensive when it prevents guardrails. You see it in a risky bet defended as “confidence” because backing down feels costly. A clean stop line prevents optimism from keeping a failing bet alive long after the evidence turns.
Tom DeMarco is a reminder to audit the argument, not the intention. State the win you are buying and the cost you are taking on, so it cannot hide inside execution. A clear line beats a long explanation.