Yeah, I've tried that explanation as well. I think the problem is that privacy as a problem is fairly abstract and multi-branched in both issues and logic.
Cheapest privacy lesson they'll ever get.
(The point: privacy about who is allowed to acquire the valuables. The owner is in control, not someone else. Once they decide to give that away: fine, now it's no longer under their control.)
Sometimes I think the issue is not being personalized enough, as in, because they do not know the person doing it, it is not an issue. It is an issue if it is you, standing next to them, but it is not an issue if you would be out of sight. It is silly.