Why would the belonging of the accounts to different people be a banable offense ? Isn't that the original point of RAF ? No matter all accounts are played on the same IP adress as there may be several computers in the same household. They have no way to tell who is really behind the computer unless you say so publicly, right ?

I'd guess they'd be way more suspicious regarding several accounts being suddenly created and added on the same battle.net account under the same name.