Thanks for the links! From the first one:

The really key idea in cryonics is the idea of freezing (or otherwise preserving) people when we don't know if we can ever revive them. Of course, we intend to figure out later whether we can do this. We intend to succeed in reviving them. But before we've actually done so, we certainly can't prove we will succeed. And funny thing, after we've done so, the proof will be irrelevant.

[...]

We can say that a condition is incurable (meaning permanently incurable, not just incurable by present technology) if the information is permanently lost. Without any means to put patients in stasis, doctors must decide what is curable and incurable in a hasty fashion. Nobody can afford to wait. But with cryonic suspension, there is no hurry at all. We simply don't have to decide that someone is gone until we have full and complete understanding of what happened to them. Before cryonics, the patient was assumed dead unless proven otherwise; after cryonics, we assume that the patient is alive unless proven otherwise.

From the second link:

The most serious ethical problems of non-ideal cases arise in the context of “last minute” cases. A “last minute” case is a case in which a cryonics organization is contacted when legal death is imminent, or has already occurred, for a non-member of the organization.

These cases typically involve distraught families, high emotion, lack of informed consent, and even lack of patient consent when the patient is unconscious or already legally deceased. Families are faced with the decision of paying a large amount of money for something they do not understand, is not likely to work, and that cryonics organizations can barely defend. Such cases conform to the worst negative stereotypes of cryonics preying on grieving families for financial gain. “Last minute” cases are rarely accepted by Alcor for many of these reasons.