Yeah... as the mods said before, this is to clarify that, even though they may not be able to prove it, it's still bannable. This is to stop people posting methods on how to do dual accounts on 1 computer.
And this is like any other rule/law/regulation... if you drink drive, but you didnt get caught, you're still free of trouble. But if they do catch you, in one way or another, you've broken the law and they can arrest you.
So I reckon if they do happen to find people abusing this rule, the GMs have all the right to ban them.