Instead, why not delete all content on the thread. Replace it with a message explaining why the thread content has been deleted and lock the thread so that no messages can be added.
This will keep the thread on people's threads I'm on, so if someone's contributed to a thread they know what's gone on. It will stop the endless spin off 'why was this thread deleted' and most importantly - mnhq explain their reasons. People like to know why something has gone poooof!
what do you think?