I wasn't trying to suggest that the book of Revelation is the only reason to support the idea of privacy as a fundamental right. It is of course possible for p

I wasn't trying to suggest that the book of Revelation is the only reason to support the idea of privacy as a fundamental right. It is of course possible for people to support that right for many other good reasons. However, I'm not sure if the "plainly stated text" of Revelation really has such a clear and unambiguous interpretation. Compare Revelation 19:16 which also talks about someone having a name written on them, which I don't think anyone would take literally, and they certainly wouldn't the previous verse where a sharp sword comes out of someone's mouth to strike down nations. You may not find these interpretations helpful, but others do, and it's fine to see things differently. Also, you're right that Roman censuses would be well known to individuals living in the first century AD, as was the practice of branding slaves, so these would be natural analogies for the writer to use to convey spiritual truths, and perhaps more complicated as-yet-uninvented systems.