Add a tag or a theme_ function to allow changing the display_mail in block_form

In simplenews_block_form there are:

    $form['display_mail'] = array(
      '#title' => t('User'),      
      '#value' => check_plain($user->name),
    );

Can you change it with?:

    $form['display_mail'] = array(
      '#title' => t('User'),      
      '#value' => '<div class="mail">' . check_plain($user->name) . '</div>',
    );

or

    $form['display_mail'] = array(
      '#title' => t('User'),      
      '#value' => theme('display_mail',check_plain($user->name)),
    );

I know i can chage it with a form_alter but i thinks it's better to change it in the module.