Apparently the letter is 'for real.' PO lady had not seen same, but was aware. Washington (where-ever) wants a real time survey of 'did your mail get delivered.' With (apparently) personal identifiers as to who responded. I was delighted she kept a straight face through out the conversation.
That aside, and the fact the Postal Service is several Billion dollars in the hole, how do you know if you've got good postal service? (I do know, and do.) You have mail in your box, so this is good? You have no mail so that's bad? I could see an on-line survey (and an 800 number if you can't) with a 'yes/no/comment' and be done with it. The delivery of junk mail is a good indicator the system is functional.
I really do wonder about the group of dip-xhits that dreamed this up.