I don't know, I could be leery. However, if handled right, maybe.... especially if it was something hinted at yet still uncertain or mysterious.... I'm trying to think of examples where similar things have worked, and what has come to mind was- of all things- the x-files. Specifically, scully, and the references to the fact that she has no death. And there was that one episode where her death was "stolen" from her by the photographer who had lived 150 years, because he lost his (chance to die). I guess the effective thing was that despite knowing that she was relatively safe as a main character, the viewer was never really sure...and scully believed she could be in mortal peril, as did others, so it never lessened the suspense. Just toyed with it a bit. Oh, I know I am rambling, but whatever.