From the IMHO thread some questions arise:
What if you are a designated donor of organs, but upon your demise your next of kin object to the harvest? Do their wishes trump those of the deceased?
What if you’re barred from harvest due to being gay, but your driver’s license shows you to be a donor? Would a viable recipient be allowed to die because his matched donor lived a “risky” lifestyle but had no confirmed disease?
When you die, you are no longer here. The desires of the living will (generally) be honored over the recently departed. Further when you die your body is no longer your property. The owner can decide.
As for the other thing, I suppose policies would hold if only for safety and liability reasons.
They used to have big advertisements that made it clear that you better make your wishes clear to your family because once you’re gone that card means nothing.