No window office buildings could become the building boom trend for the alphabet soup group. As it is, you can't find an address in a phone book for any federal agency any more. This is very signifigant. When they have to hide from the public in fear(of course they will offer other reasons) things are not going well in this country for them.
You banged right into it.
...there's no Federal Agencies in the phone book any more...
I don't know where you live, but the St. Petersburg, FL phone book has a load of Federal Agencies starting on page 12; look under the letter U for United States Government. Why it has a Federal Information Center (toll free) number, Customs, Immigration, VA, and OH! even the FBI, replete with a phone number AND an address.
Well, what do you know about that?