I see two possibilities. One, the state of my body affects what will happen to me. Two, I am mostly dead, and cryonics (and some future tech) could save me.
The first requires something supernatural. My probability: "no way in hell". The second requires cryonics to work. In theory, in practice, economically, and for me in particular. My probability: "one hell of a long shot".
Even if my organs do matter to my dead being, doctors still have lives to save…
(by the way, I'm pretty sure that's what inspired the live heads in jars in Futurama.)
I'm not sure I need my heart, kidneys etc. for future reconstruction. Important information might be located in the gut, but I'm sure we can extract many organs without touching those neurons.
Even then, I may be willing to sacrifice my hope of resuscitation to save lives today. And that's if I even bother registering for cryonics —as tempting as it is.
I'm also good with door number two. If you are to be cryonically preserved then you should not even need to opt-out as you are not "dead".
Straw man argument. People don't die with immediate effect for lack of public data.
> "The state isn't invading your corporeal sovereignty". It is, in the most fundamental and intimate way possible. If you support opt-out at least be honest about what it is. I carry an organ donation card but this is a line I think should not be crossed. There are alternative which don't make your body ownership opt-in (like doctors guidelines about approaching families etc).
You are dead. What rights do you really need and how are they violated?