I mean, Sansa convinced Jon to go to war with Ramsay to rescue Rickon. And then, the night before the battle, she said Rickon was a list cause. That's pretty messed up.
Well yes and no. Before she wasn't even sure he had Rickon, she used the prospect of him being prisoner to push Jon to fight for Winterfell, which is admittedly manipulative on her side, remember Jon here asks that they aren't even sure the pink letter is for real and she's like "yes we are!", however she is the one that demands proof when they meet with Ramsay. Once she got proof you notice she changes, she storms off, at that point she knows Rickon is lost.
Also she expected more men.