It's all in the color, isn't it? We've seen it time and time again. There's a certain limited range of shades which guarantee survival. In fact, that part of the color wheel means staying in the world whether you want to or not, even if you should have passed on long ago.
So in the end, it's not that her fur means Fluttershy CAN'T die. It's more that the network isn't going to LET her.
(Original story inspiration by Fan Of Most Everything.)
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