Facebook’s own Help Center FAQs say it’s not possible to keep your friends from tagging pictures of you (short of asking them nicely, I suppose).
You can tag a photo with the name of any friend or public page, regardless of whether you’ve been associated with them in the past. You can also just tag it with freeform text, such as someone’s name. Facebook allegedly offers a way to add their email address to notify them they’ve been tagged, but damned if I could figure out how.
Facebook’s privacy controls do appear to let you set the control for people who can see photos and videos you’re tagged in to “Only Me.” But in my tests, photos tagged with my name, using this privacy setting, still show up on friends’ pages. I can’t speak for Facebook, but that doesn’t fit my definition of “Only Me.”
The good news? According to this Help Center Page, Facebook does appear to offer a way to remove your data from its facial recognition database – which would likely assuage the fears of a great many people. To wit:
You can also request that we remove the summary of what your tagged photos have in common. On the Privacy Settings page, click Customize settings and use the controller labeled, "Delete Photo Comparison Data" if you don’t want it to be stored. This won’t untag photos you’re tagged in but will delete the summary information drawn from comparing any tagged photos of you.
Just one problem: If there’s a "Delete Photo Comparison Data" in Facebook’s privacy controls, I cannot find it.
Then again, I could just be missing something obvious. Because I fundamentally don’t understand how Facebook works.
(I’ve asked for more clarification on these matters, and will update this post if I get any.)