Can we decrease the risk of worse-than-death outcomes following brain preservation?

A "do not resuscitate" kind of request would probably help with some futures that are mildly bad in virtue of some disconnect between your old self and the future (e.g., extreme future shock). But in those cases, you could always just kill yourself.

In the worst futures, presumably those resuscitating you wouldn't care about your wishes. These are the scenarios where a terrible future existence could continue for a very long time without the option of suicide.

3) Digital blueprints of preserved brains are made available for anyone to download. Large numbers of simulations are run by kids learning how to use the simulation APIs, folks testing poker bots, web search companies making me read every page on the Internet to generate a ranking signal, etc. etc.

Easy, if you are worried about worse-than-death life after revival, don't get preserved. It's not like there are too few people in the world and no way to create more. I'll take my chances, if I can. I don't expect it to be a problem to self-terminate later, should I want to. I don't put any stock in the scary scenarios where an evil Omega tortures a gazillion of my revived clones for eternity.

1) Do you think that an opt-out clause is a useful-in-principle way to address your concerns?

Yes. In principle, you should better achieve your outcomes if you have more precise instructions. In principle, this seems sort of obvious.

In practice, I see two problems:

1) If the agency misinterprets your instructions.

2) Ambiguous instructions could facilitate corruption. In the same way that ambiguous laws do.

I'm not sure whether the upsides (more precise instructions allow you to better achieve your outcome) outweigh the downsides (1 and 2). My intuition is that I'm ~65% sure that the upsides outweigh the downsides, but that doesn't reflect much thought.

To me one solution is that it seems possible to have an "out-clause": circumstances under which you'd prefer to have your preservation/suspension terminated.

This runs into a thorny ethical problem. It's like assisted suicide, except you're neither terminally ill, nor in a vegetative state, nor in extreme pain. Since you don't have anything more than a vague idea of the future, you're unable to provide the kind of informed consent necessary for this sort of thing. A friendly future is more likely to revive you and provide you with the appropriate psychiatric resources.

A future can bring unexpected benefits. What if some positive event happened that would offset any kind of literal terminal condition? For example in a future that had nuclear war but everybody is telekinetic, how can you have a standing will on what to do if you never seriously considered telekinesis being possible?

The circumstances under which I would opt to be killed are extremely specific. Namely, I would want not to be revived if I were to be tortured indefinitely. This is actually more specific than it sounds: in order for this to occur, there must exist an entity which would soon possess the ability to revive me, and an incentive to do so rather than just allowing me to die. I find this to be such an extreme edge case that I'm actually uncomfortable with the characterization of the conversation. Instead, I'd turn around the result in question: under what circumstances do you want to be revived?

Trivially, we should want to be revived into a civilization which possesses the technology to revive us at all, and subsequently extend our lives. If circumstances are bad on Earth, we should prefer to defer our revival until those circumstances improve. If they never do, the overwhelming probability is that cryonic remains will simply be forgotten, turned off, and the frozen are never revived. But building a terminal death condition which might be triggered denies us the probability of waiting out those bad circumstances.

tl;dr Don't choose death, choose deferment.

3) Can you enumerate some specific world-states that you think could lead to revival in a worse-than-death state?

Any sort of Hansonian future, where your mind has positive economic value.

With 1): This may be an obvious problem, but if the singularity for instance occurs thousands of years in the future, then whatever language you write your "do not revive" order in, the future civilization may not be able to understand it and therefore might not necessarily respect your wishes.

With 3) Perhaps if future civilizations who were not interested in revival for its own sake (why would we want another person from so-many-years ago?) would only revive when there is a substantial depopulation crisis (e.g after nuclear war, asteroid strike etc.). If so, these conditions are unlikely to be very pleasant. However, one could argue that in those cases you have a moral imperative to stay alive and reproduce and not commit suicide, because if the crisis is temporary, then all the future utilions of your possible descendants are lost and the human species as a whole is more likely to die out.

Over the past few years, a few people have claimed rejection of cryonics due to concerns that they might be revived into a world that they preferred less than being dead or not existing.

Uh, plenty of born are born into worse-than-death situations already, at least by our standards, yet they generally make a go of their lives instead of committing suicide. We call many of them our "ancestors."

I get a chuckle out of all the contrived excuses people come up with for not having their brains preserved. I really have to laugh at "But I won't know anyone in Future World!" We go through our lives meeting people every day we've never met before, and humans have good heuristics for deciding which strangers we should get to know better and add to our social circles. I had that experience the other day from meeting a married couple involved in anti-aging research, and I got the sense that they felt that way about me, despite my social inadequacies in some areas.

As for revival in a sucky Future World, well, John Milton said it pretty good:

"The mind is its own place, and in it self/ Can make a Heav'n of Hell, a Hell of Heav'n "

Besides, if you have radical life extension and some freedom of action, you'll have the time and resources to find situations more to your liking. For example, suppose you wake up in Neoreactionary Future World, and you long for the Enlightenment sort of world you remembered in the 21st Century. Well, find your place in the current hierarchy and wait a few centuries. The Enlightenment might come around for a second go.