If I have a function that's only ever used inside of another function, I don't think it should it require documentation:

/**
 * Find capitalized words.
 */
var capitalizedWords = function(words) {
  var isCapitalized = function(string) { return string.match(/^[A-Z]/); };
  return words.filter(isCapitalized);
};

In the above example, isCapitalized would never be accessible to anyone. This doesn't seem much different from not documenting the anonymous version:

/**
 * Find capitalized words.
 */
var capitalizedWords = function(words) {
  return words.filter(function(string) { return string.match(/^[A-Z]/); });
};

Would an option for enforceExistence to let these go undocumented be a good addition? Would it be hard to add?