I don't use Facebook, and my friends and family know that and understand that I would prefer not to have them share information about me with Facebook either. As far as I'm aware, everyone I know respects this, and it has caused 0 awkward social moments.

So you'd better believe I would ask someone to turn off recording devices if they're not being used for a sensible reason. I'd be polite about it, of course, the first time. After that, well, anyone who would need asking twice isn't likely to be someone whose opinion of me I care about very much anyway. And I'm willing to bet that any resulting footage of me educating the offending party about privacy and manners right to their Google Glassed face is not going to cause anyone I care about to think less of me either.