It's not just posting photos that can cause this kind of trouble. I get a lot of email intended for other Doug Webbs sent to my gmail account, with variations on the presence/location of periods, or CC'd with another gmail account that's the same but with numbers on the end. For a while I was getting boarding passes from a major airline for a Doug that was frequently flying up and down the US west coast. Those emails gave me the confirmation number, and a link directly to the page that would let me make changes to the reservation, with no security barrier at all.

Granted, this most likely was caused by that other Doug providing my email address to the airline, but the airline is at fault too for assuming that access to a given email address is proof of identity. That's a very common mistake, often made intentionally to provide a more "user-friendly" experience. Had I been malicious, I could have caused that other Doug a lot of un-friendly grief.

I was not able to see any contact information on the reservation, and I didn't have full access to his account. (I don't know if a "Forgot Password" request would have given me that, though it probably would have.) I contacted the airline customer support to tell them they had the wrong email address on the reservation and they should contact their customer through some other means if they could. I think I got a form-letter thank you and never heard from them again, but I did get a few more boarding passes for a while.

I also get a lot of online shopping order/shipment confirmations, and plenty of personal correspondence. I try to tell the senders to fix their address books, and when I get a CC with the real address I contact the other Dougs too, but most of the time there's no response. I've had to set up a filter that puts all email with TO addresses that aren't the one I use into an "Other Dougs" folder, which I treat like spam.