This is an issue in relation to the JWs which is particularly close to my heart. I'll explain why....
My mum (whom I love dearly), while still a relatively young dub, developed complications when she was pregnant with yours truly that brought the blood issue into play, and she refused transfusions despite the doctors' warnings that both our lives could be in danger.
Needless to say, we both survived (a fact I ascribe to a greater power in spite, not because of my mother's JW beliefs) and, growing up, I was actually proud of my mother's 'faithful' stance (the power of cult indoctrination is truly mind-boggling ).
Looking at the affair now from my post-exit perspective, of course, I am truly astounded (and disturbed) at the extent to which religious/cult brainwashing can override the most basic of positive human instincts (regarding both my mother's decision and my attitudes to it while a part of dubdom).
To get to the point you originally raised, KW, my attitude on the issue tends towards that of "if you want to die for the sake of your religious/political/other beliefs, be my guest, but don't presume to drag those without power or a voice into your martyrdom" (although others can still be deeply affected - the thought of any of my JW loved ones ending up in a 'blood issue' situation now is one I prefer not to dwell on).
All this from a religion that cites scripture stating that God sees the unborn child and that condemns abortion as murder (interestingly, the same religion that holds that there is no resurrection for stillborn babies - the unborn child is evidently enough of a human person to make abortion murder, but not enough to warrant resurrection - doublethink, anyone? )
Such policies and doctrines are emphatically NOT the product of a religion that represents a loving God - certainly not of a God who deserves anyone's worship.
Sorry if I rambled and missed the point slightly, but I just felt the need to share.