The trouble is as follows:

Any cryonics organization that makes a plausible public pledge to care for the patients of future cryonics orgs that fail suddenly accepts some risk. (Though much of the cost of cryonics is the initial procedure, there would also be transport and secure warehousing costs associated with accepting the patients of a failed org.) This cost is most likely passed on to its current members.

Any cryonics organization that does not make such a pledge can therefore provide cheaper care at a comparable standard, with the added benefit that in the event of failure, the patients of these orgs will be transferred to an org of the first type, should any exist.

One solution, as far as I can tell, is for orgs that wish to be of the first type make a plausible promise to not adopt outside patients, but then make "one-time exceptions" where possible when other orgs fail. (By analogy with Kant's practice regarding marriage.)