John Aquila - I know here in the U.S. when JW kids need a transfusion, the government just takes over. And the parents give a sigh of relieve. So the kid here are covered.
As far as I know, that depends on the state. Some states still recognize the right of the parents to choose. While that can be overridden by a court order, they have to obtain that first in some states before they can take action. In my state, the doctors have a standing order to do what's necessary and they have the backing of the court so they don't have to wait for a court order.
The issue with talking to the patient privately is that even if the JW patient wants blood he still has to worry whether or not someone might see the bag of blood hanging there. It's not like it can be hidden. So even if the doctor talks to the patient privately, the JW patient is still under coercion.