That's clever! I'd assumed the hand pose function was hard-coded to only accept hand actors, so I never tried that.

Edit: now I think about it, I'm wrong - I did know about that. Back in the days of Poser 4, once MAT poses were invented, it was very easy to fill up your library. We used to rename our MAT poses as cameras to get around that. You could also rename them as hand poses, except that the Left-Right dialog was a bit of a pain so not many did it that way.

Poser doesn't care about the file contents - but apparently it is hard-coded to only set keyframes on the actors if and only if you use the hand pose function.