By the time an executor has been appointed and everything goes through probate...
I guess I should have expanded on my thought. In my state they put Organ Donor info on your drivers license.
I have always thought it would be a deciding factor in how far ER staff would go to save someone...
With modern technology, it would be a simple matter to encode a scanner readable code on the license that retrieves the info of whether or not someone was an organ donor. Or simply a phone number that a doctor can call and type in your license number to get your status.
To verify if you were an organ donor, they'd still need your drivers license whether the "ORGAN DONOR" info was printed in plain text, or an encrypted code that needed to be scanned, or touch-tone entered into a phone based system.
The difference is there would be a time/date stamp on the computer or phone lookup -- and it would be easy enough to install safeguards to be sure the lookup after the declared time of death.
It would insure your privacy about your status as an organ donor and provide a protection against a doctor who might be swayed to not take heroic measures.
Some doctor might have certain prejudices against a near dead drunk driver, suspected criminal, minority, or other person and the "organ donor" status might trigger their God complex
and get them thinking "hmmm.. the organs are worth more than their life".