"Procedures age faster than the work they attempt to control.
Standards exist for the moments when you are tired, rushed, or politically pressured. In a discussion about who has decision rights, they keep improvisation from becoming policy. When they are vague, enforcement becomes personal.
In a discussion about who has decision rights, people comply with what is enforced, not what is written. If exceptions are informal, you end up with a standard no one can defend and a process no one trusts. If you cannot describe the boundary simply, the boundary will not survive escalation and reorgs.
Diane Vaughan is useful here because it forces precision. Write the bar as a yes/no check, then name the exception trigger and decision owner. Keep it short enough to remember under stress.