The resources required for this attack are.....a laptop computer from Wal Mart for doing database queries (approx 200 billion entries per year for USPS) , an algorithm that needs to be made one time, and some input (which is apparently gathered in the normal course of mail sorting anyway, and trivial to store for future analysis, and apparently IS being stored for analysis by various countries). It would probably be more expensive for them to *not* do these sorts of attack, in terms of expense to bust ratio. also intersection attacks are pretty much a law enforcement investigative primitive....so are correlation attacks and fingerprinting attacks. also remember that just because an attack sounds advanced to you doesn't mean it is advanced. You have no investigative or intelligence training. Your grandma probably thinks that being able to use thunderbird is advanced computer skills, but to someone who has technical skill it is seen as pretty trivial.