Flags - show a flag marker even if user cannot modify it I have been able to set up a flag with Advanced forum to allow users to mark comment in  a thread they started as an accepted answer. It was simple to set up and works well. 

However, it seems Flag only alters a comment if the user has permissions to set/unset the flag. I want a tick to appear on a comment which has been flagged which any (even anonymous) users should be able to see. How do I go about doing that?
You could add a new boolean field Answer to comments which has a default value of 0. Next, create a Rule that changes the boolean value of a flagged comment to 1. The rest is theming; use the following code in your comment.tpl.php file:

&lt;?php if ($comment-&gt;field_answer['und'][0]['value']): ?&gt;
  &lt;mark&gt;This is the answer&lt;/mark&gt;
&lt;?php endif; ?&gt;