In the world of high angle rope rescue, we have a concept called the &quot;whistle test&quot;. The idea is that if someone were to randomly blow a whistle at _any_ point, and everyone let go of whatever they were holding, that no one would be dropped.<p>It takes a lot of thought and planning to make sure you&#x27;re &#x27;default alive&#x27; in all circumstances. It slows you down, and it requires you to think through the implications of every decision, big and small.<p>This sounds like a fairly similar notion...