Some games have "motion blur" as an effect, how do you know that this isn't one of them?
In any case, you could tell from the way that it was added to the character races screen and the fact that this would be an absolute customer service nightmare for Blizzard:
"Hello?....No, sir, I cannot change your partner assignment on your two headed ogre...no, there's nothing I can do, sorry, goodbye."
"Hello?....No, mam, I cannot change your partner assignment on your two headed ogre...no, there's nothing I can do, sorry, goodbye."
Continue ad nausium.