I would assume a device that records data is already fair game for evidence by legal means. If you want to get technocratic about it, you'd need to start arguing that this kind of tool is an extension of your mind/consciousness of which you are currently entitled privacy to (probably more due to lack of tech than strong ethics). But there's no tech the government does not want to regulate, so your version is probably right.

"Say, that's a nice 'democratic' governmental organization you have there....would be a real shame if something was to happen to it."

I wonder if that memory thing Dumbledore had was open to Ministry subpeonas...

It doesn’t apply to paper documents either. Though it does apply to your passcode :)