Can anyone explain to me why people are taking things happening in the show as eventualities in the book? It's been established since the beginning of this season that the two are 100% their own entities now, the only responsibilities Dave and Dan have to the source is to end at the same place. GRRM has even said this himself, and there's already several plot threads that have gone way off course from DWD and AFFC. Stannis ordering Shireen's death is a character moment, just like Sansa agreeing to go to Winterfell was - both of them probably end up having no significance in the endgame.
No one was even suggesting that Stannis would be the one to kill Shireen before Sunday's episode. People thought Melisandre might do it, but I never saw one peep about Stannis giving the order. Considering we've been writing off the show for every single character thing they've changed so far, why is this suddenly something that's for certain happening in the books? There's nothing to back it up in the text up to this point. I'm willing to believe it might happen down the line in an extremely different set of circumstances, but even then it's uncertain.