its not a bank account balance its steem blockchain wallet, it is up to the user t simply not reveal who they are! But we will have black steem, picokernal talked about that, and its definitely happening also thejohafiles talked about it last year, hah the richer the steemian the more interested they are in funding private steem accounts,
The answer is on EOS not steem, EOS will facilitate the privacy from the beginning
So what is "black Steem"?