excludeFormField = function (formField) {
      return formFieldReferencesOtherKey(formField) ||
        formField.items && !!_.some(formField.items, function (item) {
          return excludeFormField(item);
        });
    }
Helper function that parses the given field and returns true if
it references a key that is not one of the keys to include somehow
(either directly or through one of its descendants).

@function
@param {Object} formField The form field to parse
@return {boolean} true when the field references one of the keys to
 include, false when not