Because of their decision, certainly more will die that could have lived. The grey area, where getting a transfusion might actually be riskier than not getting

Because of their decision, certainly more will die that could have lived. The grey area, where getting a transfusion might actually be riskier than not getting one, is what they're finding out more about. That's useful to know. There are also cases that are not at all grey areas, where refusing transfusions means they will die. They're still refusing them (and unfortunately, that death doesn't provide any useful data, beyond "yes, what we were sure would happen, happened").