True but, all the same, drunk/stoned people equipped with phones are very dangerous for your privacy. They are actually dangerous whether they are drunk or sober, especially if they are clueless about Facebook's privacy settings.
Mine are set in such a way that you can't add me as a friend if you're not already friends with a friend of mine. If we then are friends, you can't post anything to my wall nor can you tag me in any way without my consent. Granted, the picture will still be there (and possibly visible by anyone if it was posted by one such clueless individual), but then again deleting your Facebook account won't magically erase all the pictures you appear in either.
The actual problem is that any idiot has a smartphone and a Facebook or Instagram account. And they take pictures. And post them.
There doesn't need to be any aunt following your friends. A cousin is more than enough. And there are countries where related families tend to be scattered over a relatively small area, so having friends in common between you and your relatives is but a rare occurrence.
I believe that if you are tagged in the photo (which resolves to a link to your account) then it is possible for that photo to show up in any of your Facebook friends' feeds (if your sharing permissions are too broad). However, once you delete your account I'm not sure if Facebook scrubs all those linkages.
