I think something is going on that we are not seeing. Little Finger told Sansa to use Brianne to take care of Arya but instead Sansa sends Brianne to Kings Landing. Sansa certainly looked scared when Arya asked her if she wanted to play the game of faces but then Arya gives her Cats Paw (hilt first) and walks out of the room. I think Sansa is manipulating the situation to put Little Finger in a corner because I think she assumes Little Finger is watching her and manipulating Arya and she knows how Arya got the letter. Just my opinion but I don't think Little Finger makes it past this season and I think Sansa is going to put an end to him. I'm not certain if Arya and Sansa are working together or if it's just Sansa manipulating the situation alone. My sense is that Arya is in on it and plans to protect Sansa which is why Sansa was comfortable sending Brianne to Kings Landing. I think the interaction between Sansa and Arya was an act for Little Finger to witness. All just part of my silly ass wild ass theory.
Agreed. I understand that Littlefinger helped Jon Snow and Sansa defeat Ramsey's army, but it should be pretty clear that he's just playing them both at this point and he is trying to get Arya out of the picture. I wish Bran would just tell Arya and Sansa what's going on, he sees everything, and knows what Littlefinger has done and will do. Honestly, when time travel elements are brought into a show, I lose interest. Somehow, GoT keeps me intrigued.