Place CSS around protected node

Hello,

I'm trying to put a DIV and a class around the protected node when it is viewable anywhere in Drupal i.e. in the search results or when a protected node is in preview mode via a taxonomy. Putting a class around the protected node will increase the usability of this great module so that users who stumble upon the protected node will know the node is password protected.

I was thinking I would place the Div and class in node.tpl.php somewhere or would it go into the module itself? I'm a theme designer not a programmer so forgive my lack of knowledge.

I tried to put the below code in my node.tpl.php but it didn't work.

<?php if($node->protected_node) {
print "<div class=\"teaser_lock\">Hello, This Node is protected!</div>";}?>

Thank you