A valid point, that certainly happens in a lot of cases. However, I think the main thrust of the open letter is more of a "protecting sources" concern rather than a "preserving the footage from being seized/destroyed" one. In that view

encrypted camera -> authorities cant get in -> they just smash it instead

is a beneficial outcome.

Many phones function this way now, automatically uploading photos to Google's or Apple's servers. I know it's not really as good as uploading it to a rogue operator's secret vault in the side of a mountain, but it does provide the basic protection from device destruction discussed here (and you could probably configure a Dropbox-style private cloud to upload to the mountainside vault anyway (something like OwnCloud may already do this?)). Many professional cameras have wifi capabilities, either as an add-on or built-in, that can be configured to transfer photos from the camera to the phone. You can then set that directory as a cloud backup target and it should take care of the matter.

This was exactly my thought. Encryption doesn't inherently protect availability, and by far the more common occurrence (at least the stories I've heard, from independent journos covering the US, or abroad in places like North Korea or China) is deletion. To the point where I was advised that, if I started shooting protests domestically, I should always carry a spare memory card (loaded with innocuous shots) and get good at discretely swapping them out.

I think a bluetooth pairing with your phone that automatically synced shots, though a massive battery suck, would be a better option than satellite (and easier to package in the camera body; bluetooth units are tiny), and certainly more helpful than encryption.

To be clear, I'm not saying encryption wouldn't be useful; I absolutely thing it would (and it's the business I'm in anyways, but for IoT and not cameras). But I think auto-sync has a much, much larger addressable market, and I think it also would have a larger immediate impact. You could also set it up such that the data is only stored on the camera until it is uploaded, and then immediately deleted, making it significantly more difficult for authorities to recover (if you zero the bits out properly, etc etc).

> As mentioned, a "satellite camera" that transmitted all pictures somewhere else and stored nothing is a much more worthwhile goal.

you can do this right now with inmarsat BGAN streaming, but are you prepared to pay between $5 to $20 per megabyte? that can add up quick.