[thaumaturgy]

This is answered directly on their website. They record the video in a way that supposedly makes it impossible to determine if video has actually been recorded at all.

Thus, you can simply say, "Well, sure, I've got the box, but it hasn't been recording anything", and nobody can prove otherwise.

I'm still reading the site to see if I can understand the technical basis for their claims.

[robotrout]

This is exactly the same premise as TrueCrypt. Nobody can know if there's anything on a TrueCrypt volume or not.

They address the coercion (either by law enforcement or guy with a gun), by allowing you to make hidden volumes inside the main volume. You open the main volume, filled with data you don't care about, and they never know that a hidden volume resides deeper.

I see no reason that this same technique wouldn't work here. You record some boring video on the main volume, and record your main video on a hidden volume.

[thaumaturgy]

IIRC, some minor vulnerabilities to TrueCrypt's DFS were found.

Ah, found one link: http://www.schneier.com/paper-truecrypt-dfs.pdf