All the people currently signed up for cryonics but not dead.
Alcor at least also requires boardmembers to have loved ones currently in suspension so there's another incentive.
Let's suppose it's 50 years in the future and you're signed up for cryonics with, say, Alcor. How confident are you that you'd know if Alcor had quietly disposed of some of their patients from 50 years ago?
If your answer, like mine, is "not very", then how strong an incentive do you think the fear of lawsuits from other signed-up people is, against any temptation to dispose of old patients to increase their profits?
(I am not suggesting that they do, or should do, that. Only that that particular incentive probably doesn't change their behaviour much.)
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.