If they're committed to the position that privacy is not valuable in it's own right, for it's own sake, then you might suggest to them that they put a webcam in

If they're committed to the position that privacy is not valuable in it's own right, for it's own sake, then you might suggest to them that they put a webcam in front of their toilet. "Nothing to hide" usually means they don't realize just how much can be known about a person from the trail they leave online.