For full 2.7 compatibility, you have to modify WPMU Trident to use the new nonced logouts:
in comments.php, line 126 change:
<?php echo get_option(‘siteurl’:wink:; ?>/wp-login.php?action=logout
To:
<?php echo wp_logout_url(); ?>
And do the same on line 39 of profiles.php
Cheers,
Chris