appearances matter move to switzerland

That is not what I was talking about. That case stands for the relatively unremarkable proposition that you can't be compelled to decrypt data when the government has no idea what it is going to get out of that decryption. As the opinion says in a footnote:

> That said, if the Government is unaware of a particular file name, it still must show
> with some reasonable particularity that it seeks a certain file and is aware, based on other
> information, that (1) the file exists in some specified location, (2) the file is possessed by the
> target of the subpoena, and (3) the file is authentic.

But that is defeated just by regular full device encryption. You don't need hidden volumes to get there. Granted, the court did talk about hidden volumes, because that was the particular technology that this defendant chose to use, but in my reading, full device encryption would have done just as well.

The original use case for hidden volumes was altogether more bizarre. The idea was, roughly speaking, that you might end up in a situation where some authority (legitimate or otherwise) is threatening you (with rubber-hose cryptography, criminal charges, or whatever) if you don't decrypt your hard drive, and you "comply" by decrypting the innocuous non-hidden volume. But that has never made any logical sense, because you have to leave a large hole that never gets decrypted, which will make it hard to plausibly deny the hidden volume's existence. Moreover, if the authority is legitimate, lying about the hidden volume is not only a crime, but it may constitute a waiver of any Fifth Amendment rights (or the local equivalent) you might otherwise have had. It's actively making your situation worse, for no upside.