Are you sure that “remove topic” isn’t just moving the thread to another “trashcan-like” sub that all mods don’t have permissions to access, and the thread is moved to this sub in those situations? I think it would be very non-optimal if a thread was really “deleted” but is still available in database backups somewhere.
Mmmm I found this :
Deleting Topics
You can remove an entire topic, including all of the replies, by going to the bottom of the topic and clicking on the "Remove Topic" button.
Restoring Deleted Posts and Topics
Deleted posts and topics can only be restored if a recycle board has been created. Moderators should ask their forum administrator whether a recycle bin has been enabled.
You are right when you say that when a topic is deleted it is moved to the trashcan, but in fact there are 2 trashcans
