I don't think anyone would knowingly risk their life for a diet. If they thought it would/could result in death I don't think they would! The first case is anorexia, I don't care what the article says. If you live on apples and water for months it's not a crash diet, it's an eating disorder.
Still, crash diets don't work! We all know that I don't think diets like LL are crash diets though, they are carefully controlled so your body gets what it needs.