Its a reflex to refuse blood. When however faced with the real consequences, I think JW family will more often reason "if I allow it, then I am the one that is responsible.....not _____ since she was unconscious."
In a situation regarding my family, a doctor told us to remember that they are a teaching hospital, and they WILL respect our wishes. Which means if we won't allow blood, then they won't even bring it in the room. But what the doctor said after that was what stuck with me.
"We have found more often than not in these situations that the family or even the person at risk will change their mind, leaving us scrambling for supplies we did not bring close in order to respect religious objections. So I want you to know......we will keep your medical situation completely private."
THAT....made an impact. I would put it in the column for a lot of JW's take blood.