I think it's like with any other believe - the more people saying that's someting is true the more people starts to believe it. I haven't encounter "fand death" believe till today and probably that's why I don't believe in it. On the other hand if I would hear that constantly or even from time to time from others I maybe would start worring about it alothough my left brain side would say it's irracional. Subconscious mind can really beat s*** out of us sometimes and we even won't know where the problem actually lays. It always comes in the shade of some unplesent feeling or precognition and you end up with the feeling "I don't really like turining on fan when I go to sleep, but when someone asks you why? I'll just say. I don't know - Just feel like it.