I did some research on this, and as far as I can tell, the buff should be in the game already.
Some forum posts or blogs discussing the buff:
June 23rd, 2005 (Danish):
http://www.dailyrush.dk/rpg/boards/2240/topics/35464/May 17th, 2005 (English):
http://wow.allakhazam.com/forum.html?fo ... 2202261563April 27th, 2005 (German):
http://www.forum-3dcenter.org/vbulletin ... p?t=219437March 18th, 2005 (English):
http://www.killtenrats.com/2005/03/18/t ... ldt-manor/As far as Robotrons statement that the buff was added in 1.10, the 1.10 patch notes themselves mention under the "Mac" section that an audio issue with this buff has been fixed, implying that it already existed prior to this patch.