Allow me to set the scene. It's late at night and you're starting the last hour of a multi-hour trip home. You already knew that starting the drive so late instead of spending one more night away from home was ill-advised, but as your blinks become longer and slower you're having significant doubts about your ability to finish the trip. Just as you're debating the merits of stopping for a nap, the unthinkable happens. You nod off, cross the double-yellow line, and crash into an oncoming vehicle.
Both you and the driver of the vehicle you hit are fortunate in that an ambulance scoops you up quickly and gets you to a nearby ER where you're both stabilized for the time being. You're doing okay, but the other driver is in bad shape. He needs a kidney and some blood. Miraculously, you're a perfect match for both.
You have a terribly hard decision. You're stable at the moment, but this seems like a risky time for you to undergo a surgery to remove a kidney, even though the victim in the accident you caused will not live without the transplant. Even donating some of your blood to him jeopardizes your likelihood of survival.
Ultimately, you make the call that you can't bring yourself to do either thing. There are many reasons that you use to justify your decision, but none of that matters--it's your call and only your call. The family of your victim goes from begging to threatening lawsuits, but there's nothing they can do. Your right to bodily autonomy is absolute. No court can compel you to use any part of your body to save the life of another person for any reason.
Out of the blue, your situation take a sudden turn for the worse. In the span of minutes you go from talking with your family at your bedside and impatiently asking when you can get moved out of the ER to being pronounced dead by a tired doctor at your bedside.
It does not matter that you were an active participant in someone needing your organs, it does not matter that you're at fault, it doesn't even matter that you no longer need the organs because you're dead. You cannot for any reason be compelled to sacrifice autonomy over your body and its parts.
Well, you cannot for ALMOST any reason. Without Roe v Wade, you can be compelled to sacrifice that autonomy if you are pregnant and you live in a state that does not protects a pregnant person from being used as a brood mare.
You know, because life is sacred.
The family of your victim rallies almost immediately. Surely, now that you've passed, they can get your life-saving kidney. In this case, your death changes nothing--you weren't a registered organ donor and your family is inclined to honor your implied wishes. Your organs die with you. Even in death, your bodily autonomy is unassailable.