Wiki · Reference entry
Critical blocker
A single failure that must not be averaged away.
Some requirements are not scoreable. A missing permission boundary, a payment that can go to the wrong account, a piece of advice that could hurt somebody: one instance is disqualifying, and no quantity of passing checks elsewhere compensates. Ordinary readiness scores are means, and a mean cannot express a veto.
Why it matters
If your release gate is an average, it cannot see the thing that should stop you.