So what exactly was the purpose of Sansa not telling Jon that she may have secured heavy cavalry from the Vale? And surely she could’ve had the sense to get Baelish to send a raven in answer telling them that they could count on the Vale. Was it the writers simply wanting to surprise the viewers? Even Aragorn knew that the Rohirrim would show at Pelennor Fields but it didn’t cheapen the moment in book or movie when Theoden arrives.