Notice: Undefined index: date in _zen_preprocess_comment() (line 19)

Error:

Notice: Undefined index: date in _zen_preprocess_comment()  (line 19 of /Users/gareth/Sites/drupal7dev/sites/all/themes/zen/zen-internals/template.comment.inc).

Cause:

  // In Drupal 7, $date has been renamed to $created.
  $vars['created'] = $vars['date'];

If created already exists but date does not, should the code not read:

  // In Drupal 7, $date has been renamed to $created.
  $vars['date'] = $vars['created'];

Or be removed entirely unless there is a specific need for backwards compatibility?