I think there is a significant (>= 50%) probability that they don't: there have been anecdotal allegations of mis-behavior, at least one company (the Cryonics Institute) has policies that betray gross incompetence or disregard for the success of the procedure ( such as keeping certain cryopatients on dry ice for two weeks ), and more generally, since cryocompanies operate without public oversight and without any mean to assess the quality of their work, they have every incentive to hide mistakes, take cost-saving shortcuts, use sub-par materials, equipment, unqualified staff, or even outright defraud you.

Woah, really? This seems ... somewhat worse than my estimation. (Note that I am not signed up, for reasons that have nothing to do with this.)

it is plausible that before revival tech becomes available, radical life extension becomes available, and therefore people stop signing up for cryonics. Cryocompanies might be required to go on for many decades or centuries without new customers. It's unclear that they could remain financially viable and motivated in this condition.

This is a good point that I hadn't heard before.