I think an "angst" label should suffice for character death. I have put warnings on my fics for character death because it really wasn't worth the trouble to keep getting emails where people go "OMG you killed her!!!" Even with a warning I still got feedback from people begging me to make a sequel and undo the death. *shrugs*

As a writer I hate the character death warning. Why? Because it takes away a lot of impact that isn't worth it.

There is a really simple solution though, that can spare both writer and reader. I do it myself when I'm just not up to reading fic with bad endings, I scroll down and make sure the ending isn't bad. Yes, it will screw some of the surprise up. But honestly? It doesn't spoil the reading experience of people who are not touchy about the subject.