[estrabd]

> If an organization is in a position to confiscate the camera from a journalist, they're almost certainly ALSO in a position to extract the encryption password from the journalist.

This is basically why GBDE exists.

See s.s. 4.1 "Protecting the user" of http://phk.freebsd.dk/pubs/bsdcon-03.gbde.paper.pdf

The drawback is that GBDE is for cold storage protection (which I imagine could be okay in a camera).