I don't have a problem with denying organs to people who don't want to be donors. It's your right to take 'em to the grave with you , but then you can die for lack of a kidney for all I care. (not 'you', but the general you)
take this to the logical conclusion.
MANDATORY LIVING DONATION.
you don't need two kidneys, mandatory tissue typing banks SHALL REQUIRE, you donate one of your kidneys. Also applies to 1/3 of your liver since mostly it will grow back.
Of course nobody is mentioning that adult stem cells may make all this moot.