It seems like a glitch, something not caught in quality testing for Timeline, but Facebook's once again let a privacy concern slip into a universal feature, according to The Next Web.
Friends can go into a photo in Timeline and change the location of that photo --even if they are not tagged. Just parachute in, change the location to PERDITION or whatever and wait to see how your friend reacts.
Drew Olanoff did the heavy lifting of finding the privacy setting that needs changed to turn this "feature" off. Of course, it also turns off location tags, overall.
Another note on Timeline is that the mobile version is not available on iOS -- only Android and m.facebook.com. From Facebook:
Mobile timeline starts with your unique cover photo. As you scroll down, you'll see your posts, photos and life events as they happened, back to the day you were born. Photo albums and other posts are horizontally swipeable, so you can quickly view multiple photos or posts inline without leaving timeline. You can also swipe through the views at the top of your timeline to navigate to your map, photos, subscribers and more.
There's no further comment on iOS or why they went Android-first.