Not sure exactly how this would be implemented, but it sounds like a bad idea, since they would just wait for your automated updater to decrypt the decoy. Even

Not sure exactly how this would be implemented, but it sounds like a bad idea, since they would just wait for your automated updater to decrypt the decoy. Even if it was in some limited fashion, the encryption key would be in RAM, so it would be as vulnerable as any running system. (BTW, if you're worried about a state-level adversary, that means you should always turn off your computer when not using it, and wait a few minutes before physically leaving it to prevent a cold boot attack)