I think one reason to expect them to keep you there is the same reason people don't always ignore their dead relatives' wills. If one promotes a culture of ignoring wills/unplugging cryopreserved people, then one increases one's own chance of being ignored/unplugged. It's sort of a bargain between generations, each generation honoring its commitment to the previous one with the expectation that the next generation will honor its commitment to them. I'm not sure how solid the game theory on this is, but it mostly works in the real world with wills.