Unfortunately that's not always possible. For example you're in a pub with your friends, and someone takes a group picture and posts it online. Even if you don't have FB account, you're there, and there's absolutely nothing you can do about it. Very annoying.
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.
Unfortunately that's not always possible. For example you're in a pub with your friends, and someone takes a group picture and posts it online. Even if you don't have FB account, you're there, and there's absolutely nothing you can do about it. Very annoying.