USPS is awful from a privacy perspective. USPS will email photos of your incoming mail to anyone who files a change-of-address form with your address as the new address. They don't require any sort of confirmation.
I know this because after I moved out of a place and started traveling for a while, I set up forwarding to my parents' address, and after clicking the "informed delivery" checkbox I immediately started getting photos of all my parents' mail.