Those who say that they think it is wrong because you simply might not have had the chance to consider it yet - consider it now! You never know when you might get hit by that bus, and yes, two people might die just because you hadn't thought about it yet.
I'm writing as someone currently undergoing assessment to see if eligible for a lung transplant. The hard fact is that there are not enough organs available. What this means, in reality, is that the doctors are not deciding on medical need, but on likelihood of survival/best possible outcome. So, if there will plentiful organs, the surgeons would decide whether or not an organ was the best chance for me, and then put me on the list to see whether some suitable lungs came up in time. I'd have nothing to lose - I am going to die anyway, and the surgeons could give me the best shot at survival by giving me some suitable lungs.
As it is, I'm not a great candidate for a transplant, in that the cHnce of success is relatively low. I had lung surgery in the past, before my condition was correctly diagnosed, so it may now be difficult to remove my lungs. For me, the best chance of survival is a lung transplant, but there aren't enough, so the surgeons are choosing between me and somebody else, who might have a better chance of the transplant being successful.
That is a difficult one to get my head around. My only chance of survival - and admittedly it is only a chance - is not happening purely because there are so few organs that surgeons choose between me and someone else. Quite rightly, but neither of us chose these conditions, neither of us created them or exacerbated them, and just circumstance has left us where we are. I'd love to say to the surgeons "I'm going to die anyway, you give it your best shot", but because of the shortage of organs, that is not for me, or even them, to say.
Sorry for the length. A rather personal matter, as I''m sure you'll see.