A few example requirements:
The ability to donate or not donate organs against their family's wishes.
The ability to forgo an autopsy if the death was under suspicious circumstances.
The ability to have their desires for their body acted on quickly, not subject to multiple days of holding the body in storage.
(Assuming they indicated these desires in some legal document.)
Related questions
>> The ability to forgo an autopsy if the death was under suspicious circumstances.
Here's one argument why this sort of policy won't (shouldn't?) be implemented: it makes murder easy to get away with and hard to prosecute. The murderer simply has to forge some documents.
From a Bayesian perspective, if a judge sees "this person agreed to forgo an autopsy", it's (I imagine) much more likely that they are looking at faked evidence. In other words: I wouldn't be surprised if fake (or somehow coerced) autopsy-waivers far outnumbered honest autopsy-waivers.
(Same argument goes for your cousin market on suicide.)
@Boklam There are already a lot of other incentives to forge document; Why would this be more of a problem than forged wills?
@IsaacKing Most wills (I imagine) are legit, because many people create wills: if you have kids and assets, you will (I think) be advised to make a will. So I would guess ~10% of the US population has gone to the trouble of making a will.
I can't imagine any similar number of people going to the trouble to say "if it looks like I was murdered, don't bother looking into it, thanks". It's a lot of trouble, and there's no clear reason why anyone would do it. So I'd expect this to be very rare -- perhaps roughly the same as the number of people who read Isaac King's blog.
Which means (I think) that the proportion of fakes is much, much higher.
@Boklam That makes a lot of sense, I didn't think about the difference in base rates.
if it looks like I was murdered, don't bother looking into it, thanks
The murder could still be investigated; they just get to except their physical body from that investigation.
there's no clear reason why anyone would do it.
Most people wouldn't, I agree. But there are certainly some reasons.
So I'd expect this to be very rare -- perhaps roughly the same as the number of people who read Isaac King's blog.
Ouch.