But, you know, stuff happens. Somebody's machine loses the hard drive; in the process of building the new hard drive, they miss restoring the configuration for their editor. Somebody else installs a new editor, and forgets that configuration matters. A new employee gets hired, and doesn't know either how or why to configure properly. And behold, bugs get introduced invisibly.

That won't happen often. It will happen more than zero, though. And when it does, it's a headache I don't need.