> The difference between having someone who always triple-checks every parameter they input, versus someone who never double-checks and just wings it. Sure, the person who triple-checks will make mistakes, but less than the other person. This is the issue I'm trying to get at.

If you rely on someone triple-checking, you should improve your processes. You need better automation/rollback/automated testing to catch things. Eventually only intentional failure should be the issue (or you'll discover interesting new patterns that should be protected against)