"Systems drift because tradeoffs are made implicit rather than explicit.
The most expensive failures are quiet ones: a series of decisions that were defensible in the moment and disastrous in combination. In a metric proposal that will change incentives, nobody wakes up wanting the incident; they wake up wanting the shortcut.
In a metric proposal that will change incentives, everyone will focus on intent. The system only feels behavior. You see it in a local optimization that creates global instability. Define the decision rights before the crisis, or the crisis will define them for you. Be honest about what would change your mind, because without a revisit signal every decision becomes permanent by default.
Geoffrey Vickers is a reminder to audit the argument, not the intention. Name the cost you are accepting so you can defend it later. Write it so execution is obvious.