If you can't spot it in the image up top, try clicking through for the hi-res. You'll know it when you see it.
Redditor adepssimius (that would be Ben) says he had to wait until the notices had been sent out before revealing his prank to his fiancée, along with the rest of the world. We're just surprised she didn't spot it before they got mailed out — she's obviously a clever girl. (I'm sorry, I had to.)
[Spotted on reddit]