Which is why the character in the show is retarded. Book Stannis wouldn't do this, the character they setup in show till last episode wouldn't do this. I think his Army would do it. But that's the difference between the book and the show. In the book not only is Stannis' Army super faithful to R'Hllor but they've been out in the cold freezing and starving for months. The show show's neither of these things. So when Melisandre comes and says "Hey if we kill this child, we will be victorious in this battle and everyone will live" I can definitely see the devout army being like "Hey Stannis, **** your daughter, she's gonna burn". The other thing is Melisandre in the book is not one dimensional like she is in the show. She's a person with real feelings and not a chick who just takes her clothes off constantly. Anyway, during this time she's seeing conflicting visions about whether Stannis is even the person she's supposed to be following. Despite that her faith to R'Hllor is devout, she truly thinks that sacrificing will bring victory and she brings it up multiple times. They haven't gotten around to doing it yet in the book. But yeah Stannis in the show, him doing that, is not believable -- it's like completely out of place and it's lazy writing. They could have easily done it differently, especially because the entire front half of this season was garbage and nothing was happening. They could have shown his troops suffering/revolting and stuff like that to build suspense. Instead of running it all out in one episode.