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					Originally posted by Eóghan Scherzy  Why did Sansa withheld the information of the Vale Army from Jon?   
- Or maybe Ramsay only planned for Jon's troops-- had he known the Vale would be there the Boltons could have strategized for them too and the battle would be more evenly-matched-- and thus they could still be defeated. Sansa also knew Ramsay in a way Jon didn't; she didn't really trust Jon to win..[/I] | 
	
 This is it.
She bore witness to the battle plans and she realized it was all based on the foundation that Jon was gonna outsmart Ramsay by laying a trap with the Wildling forces. And Sansa knew better.
The entire point of her conversation with Jon was that she knew they had to outsmart him, and in order for her to do that she had to lay a trap, one that not even Jon knew because including the Vale forces in the battle plans would've changed the whole plan for Jon and the Onion Knight.
And if Ramsay knew the Vale of Arryn was riding for Sansa he would've locked himself up in a siege in Winterfell they could never win. Sansa had to outplay not only Jon but her allies and Little Finger himself, his conversation with her back in Ep3 was intended to indebt him to her.