To answer HC, no, there should not be bars to receiving a transplant because things are not so black and white as 'are they a drug addict?', 'are they old?' etc. Someone might be an old drug addict and still do an immense amount of good in the world and brighten everyone's existence by their own and a young non addicted person might be a complete horror story of a person who causes nothing but misery wherever they go. You can't quantify the individual's effect on the greater good of the world so all must be equal.