I don't have links on hand but it is true that you are not allowed to share accounts with anyone EXCEPT in the situation of a parent and a minor child then you are allowed.



A distinct blizzard comment I remember (however much I do not agree with them) is, "Think of it like an amusement park ticket, you need 1 for each person wanting to come into the park and enjoy the rides." But this is also in the EULA and TC stating that you do not "own" blizzard characters they are blizzard property and you are basically leasing them =(.



*EDIT* They will also consider you a person selling/powerleveing a toon for money if it is in 2 different names.