Ok, i told GM i'm using Isboxer and provided some links which are related multibox blue post from Blizzard. He replied me and said ---

GM could be check in-game players randomly, and the game World of Warcraft do not including the software that i use( Isboxer ).
For security, he RECOMMENDED me to avoid that kind of software to process game. If there have any question, please contact our GM.

OK, well.... tacitly agree??? They never give me a clear and definite answer.