I had a relative that died in the 50s, and at least part of it, if not all of it, was due to refusal of blood based on WT doctrine.
I don't know for sure but I get the impression that there was a time when disfellowshipping wasn't the fear tactic it was today. People really believed that this was God's law. There wasn't this discussion about whether one would get disfellowshipped but whether or not one would be eternally condemned by God.
Today, medical technology could have possibly prevented the death (it was during childbirth) without blood. But back then, less was known about stopping bleeding and C-section alternatives, etc.
Now the ironic thing, is that had this death been prevented by my relative not refusing blood, I may not have even been born - because that would have set off a very different butterfly effect set of events.
I think back then, people trusted that their decisions, if in line with watchtower, were also in line with god. But also, as seen by some responses to the watchtower in 1945, others seemed to rely on their own understanding of the bible - even if it wasn't in line with the watchtower. Perhaps so many were in disagreement with this that in 1961 they had to "clamp down" as it were and enforce people's conscience with fear tactic of disfellowshipping.
After all, you had people literally dying for this, how did the surviving family members feel about someone that ignored the WT policy and lived? I wonder if that had some influence. One thing for sure, Watchtower really likes it when people die for their doctrine. It really is the ultimate endorsement to them.