The final piece of the DAV authentication puzzle. Provide a directory view to an un-auth'd person (without asking for a password) by adding a query parameter 'davguest=1'. This is a bit of a hack, but there was no response on the official forum about how to do this correctly so it will have to do. On the downside, if permission is denied, it won't ask for a password - but we're talking about unauthenticated folks who didn't go through magic auth so chances are even if they authenticate, permission will still be denied.

include/conversation.php

@@ -1481,7 +1481,7 @@ function profile_tabs($a, $is_owner=False, $nickname=Null){
 	if($p['view_storage']) {
 		$tabs[] = array(
 			'label' => t('Files'),
-			'url'	=> $a->get_baseurl() . '/cloud/' . $nickname,
+			'url'	=> $a->get_baseurl() . '/cloud/' . $nickname . ((get_observer_hash()) ? '' : '?f=&davguest=1'),
 			'sel'	=> ((argv(0) == 'cloud') ? 'active' : ''),
 			'title' => t('Files and Storage'),
 			'id'    => 'files-tab',