That thought crossed my mind, too. As for the other suggestion, as a fake Sansa, I think that Sansa has another part to play in the Eerie. I do not like that Ros survived the crying situation. It would have been totally in Littlefinger's character to offer teh customer the alternative whore, as he did, then find someone to escort Ros away, permanently. I kind of find the idea that Petyr would stoop to threats with Cersei and Ros as incongruant with his nature. He has a golden rule, to always keep his hands clean.