We all know about "theocratic war strategy" - it's not really lying, if the person you are speaking "isn't entitled to know the truth".
But, it suddenly struck me - this definition of lying, unique to JWs (lying is not merely telling a known untruth, but telling such to one who doesn't deserve the truth) helps them justify the blood doctrine. How so?
Well, consider the extreme example cited in the old WTs bold enough to actually name & describe "theocratic war strategy" - a country where JWs are under ban. A clandestine meeting is being held in the home of a JW - there is a knock at the door - the secret police ask "do you know where the JWs are hiding?".
Now, the person who answers the door has a dilemma - if he tells the truth - his brothers will be incarcerated, perhaps killed. But God's law says he cannot lie. What will he do?
Most normal people, with normal ethics, realize that a "greater good" will be done by lying in this case. It is wrong to lie, but it is even worse to allow harm to others, when it is in your power to stop it.
However, if the WT were to say "it is OK to lie in this case, to save a life", what precedent are they setting? "It is OK to break one of God's laws, if it accomplishes a greater good."
If that were the case, then in the case of a blood transfusion, one could (in a logically consistent way) argue that saving a life is a "greater good" than respecting a "symbol" that God considers holy. One could accept a blood transfusion when one's life was in danger.
We can't have that! So, what do they do? Well, they redefine "lying" as "not telling the truth to someone entitled to know". The secret police are not "entitled" to know where the hiding JWs are, so telling them "I don't know" is not a lie...i.e., you haven't broken God's law.
Thus, per their reasoning, there is no justification for "breaking God's law" regarding blood, even in extreme circumstances.
For those who are interested, it is worthy to note that Jesus subscribed to the "greater good" theory. He performed "work" by curing people on the Sabbath (he could feel 'power going out of him' when a cure occurred - it took effort - work). Breaking the Sabbath was technically a capital offence - yet greater good was achieved by breaking that law in extreme circumstances.
Of course, such subtlety is lost on most JWs.