Bad code in function date_field

function date_field($op, &$node, $field, &$items, $teaser, $page) {
  // Add some information needed to interpret token values.
  $additions[$field['field_name']] = $items;
  foreach ($items as $delta => $item) {
    $timezone = isset($item['timezone']) ? $item['timezone'] : '';
    if (is_array($additions[$field['field_name']][$delta])) {
      $additions[$field['field_name']][$delta]['timezone'] = date_get_timezone($field['tz_handling'], $timezone);
      $additions[$field['field_name']][$delta]['timezone_db'] = date_get_timezone_db($field['tz_handling']);
      $additions[$field['field_name']][$delta]['date_type'] = $field['type'];
    }
  }
  switch ($op) {
    case 'load':
      return $additions;
      break;

    case 'validate':
      require_once('./'. drupal_get_path('module', 'date') .'/date_elements.inc');
      return _date_field_validate($op, $node, $field, $items, $teaser, $page);
      break;

    case 'presave':
    case 'insert':
    case 'update':
      require_once('./'. drupal_get_path('module', 'date') .'/date_elements.inc');     
      $items = $additions[$field['field_name']];
      if ($additions[$field['field_name']]) {
        $node->$field['field_name'] = $additions;
      }
      return _date_field_update($op, $node, $field, $items, $teaser, $page);
      break;

    case 'sanitize':
      foreach ($items as $delta => $item) {
        //$dates = date_formatter_process($field, $item, $node, $formatter);
        //$node->$field['field_name'][$delta]['dates'] = $dates;
      }
      break;
  }
}

This function seems to have some "bad" code in it.

1. sanitize case make a foreach loop and it is doing nothing. Why is this then needed, it only takes up time.

2. only load, presave, insert and update case is using the $additions. So why do a foreach and make that variable for all items when all other $op is not using it? Time and memory that is used unnecessarily.

This code above, that these two points is about, I feel is a bit bad programming code and should be rewriten to have a better preformance on this module.

I also noted that there is a lot of require_once('./'. drupal_get_path('module', 'date') .'/...inc'); why not use module_load_include or is there any reason for that?