Gamaliel, in all the cases you mention: If they'd personally made known to me that they didn't want a blood transfusion (or medical treatment of any kind), there was no legal impediment to respecting that decision, and I had no reason to think that their decision was made without due consideration, then I would not over-ride their choice.
It reminds me of a case I read about some years ago. A social worker was making the monthly rounds of her clients; one of them was living in a rat-infested hole, and her lower legs were virtually encompassed with open lesions. The social worker made every effort to convince this lady to go to the doctor, to no avail (the lady had a morbid fear of doctors, for whatever reason.). A series of "psych" questions made it clear that the lady was not mentally deranged (legally speaking). The social worker was compelled to walk away and leave the lady in that squalid condition.
As deplorable as it was, it was still her choice.
To clarify: If I didn't know from personal conversation that a JW had made such a decision, or if I detected ambivalence in that decision, then I'd defer to the medical opinion, in a flash.
This issue isn't quite as black and white as it seems at first is it?
Personally, I think it's as black-and-white as it gets. And I do think I've moved way beyond the b/w JW mentality. One of the issues at play here, imho, is: The WTS has enforced it's personal opinions on so many of us for so many years, it's possible for us, in reverse, to display the same mentality, as a compensation reaction. To whatever extent that's true, we fall into the same trap we just escaped from.