This is pretty great too. I moved about two months ago, and switched addresses in Informed Delivery. I got a letter saying I switched, but I never put their code into Informed Delivery, and I still get scans of my mail at the new place. I got the scans before the validation letter, so I could easily have stolen that, and no one would know I'm seeing their mail....
*Edit to make things clearer.
I have not validated anything. The letter says I won't get emails unless I put the code in the letter in Informed Delivery. I did not do that ever and I still get the emails.