This has happened to me. It's definitely a risk, of course, and there's little you can do short of losing your friends and any semblance of a social life these

This has happened to me. It's definitely a risk, of course, and there's little you can do short of losing your friends and any semblance of a social life these days. You could have a chat with them and see if they're willing to respect your privacy. Nothing much that can be done about strangers who do that though. I've seen a few places that actively ban Google Glass (I think that was mentioned here as well), but there are no bans on camera phones in any place as far as I know. If a thing exists, it will be used after all. Original intent be damned.