Quote Originally Posted by traedoril View Post
Blizzard does not recognize the transfer of World of Warcraft Accounts or BNET Accounts (each an “Account”). You may not purchase, sell, gift or trade any Account, or offer to purchase, sell, gift or trade any Account, and any such attempt shall be null and void. Blizzard owns, has licensed, or otherwise has rights to all of the content that appears in the Game. You agree that you have no right or title in or to any such content, including without limitation the virtual goods or currency appearing or originating in the Game, or any other attributes associated with any Account. Blizzard does not recognize any purported transfers of virtual property executed outside of the Game, or the purported sale, gift or trade in the “real world” of anything that appears or originates in the Game. Accordingly, you may not sell in-game items or currency for “real” money, or exchange those items or currency for value outside of the Game.
This is directly from http://us.blizzard.com/en-us/company/legal/wow_tou.html

This is not in the ToS for Starcraft to YET.
To be honest, that was probably implemented because of WoW:TCG item codes and just happens to
cover the arena problem as well.