Patch 4.215 July 2011 - 02:45 AM Contributed By Tobiyo
Swap the "X" with 1,2,3 and you have a effectiv "Arena Blind" macro without targeting or focusing that arena target you want to blind. you can also add /focus after the "cast [@ArenaX] Blind" command to set your blinded target as focus, so you can see if he use his trinket or when you've dance/vanish for a resap.
You have to make 3 Macros! One macro for every arena target.