Threads Deleted threads are confusing to the end user
 

Whenever a thread is deleted, links to it may still exist on the forum. Unfortunately the deletion of the thread has no effect on the now dead link.

The dead link will send users to a permission error page:
Quote:
Invalid Thread specified. If you followed a valid link, please notify the administrator
This confuses members, lets them think there is something wrong with their permissions and lets them contact the administrator.

The message should tell the user that the thread has been deleted and therefore is no longer available.