Rails - Jul 2005 - cancelling before_destroy

According to the documentation, if I return false in a model''s 
before_destroy method then it should cancel the action. Although I know 
it is reaching and running this code, it deletes the object despite the 
"return false". I''m sure this were a bug it would have been
noticed by
now so I must be missing something but I cannot imagine what. Even in 
the simplest scenario I cannot cancel a delete. Has anyone done this?

http://api.rubyonrails.org/classes/ActiveRecord/Callbacks.html