I keep having seeing this scenario in my mind and it goes like this:
I refuse a plasma transfusion for a loved one and they die soon therafter.
At judgement day, God is deciding whether I am worthy to enter the kingdom. He says I have lived by his will to a good degree, however, I chose to let a loved one die instead of choosing a plasma transfusion.
I say "Yes, God. I refused one because of the spiritual direction that I received from the faithful & discreet slave, that you appointed. The scriptual argument for refusing blood transfusions convinced me to do so."
He says "Let me get this right. You prayed for many nights for me to direct your life and your beliefs. Then, you felt the need to start viewing material that showed the WTBTS had previously taught that serums, hemodilution, albumin, organ transplant, etc. were also unscriptual. Instead of thinking, "Hey, is it a good idea to follow scriptural interpretation of the WTBTS when it effects medical decisions?", you allowed a loved one to die by following their interpretation of blood transfusions. Did I not bestow reasoning ability and the power of logic on your life?
I say Yes, God. But I figured that......
He says "Well, I guess you figured wrong. No everlasting life for you, since you saw a pattern of error and yet still decided to follow that pattern of interpretation. You were wreckless with the gift of life.