I guess the one good thing about photographing 160 billion pieces of mail is that they have 160 billion photographs. Like the NSA, they are swimming in an ocean of data that they can't look at. No human eyes will look at the photos of your packages unless you come up in an investigation, like that woman in Texas who sent ricin in the mail. Even though she used a fake return address, they found her by looking at the cities of the return addresses of other pieces of mail that went through the system immediately before and after her letters, which turned out to be useful in that case.