13 U.S.C. § 223 : US Code - Section 223: Refusal, by owners, proprietors, etc., to assist census employees

      Whoever, being the owner, proprietor, manager, superintendent, or
    agent of any hotel, apartment house, boarding or lodging house,
    tenement, or other building, refuses or willfully neglects, when
    requested by the Secretary or by any other officer or employee of
    the Department of Commerce or bureau or agency thereof, acting
    under the instructions of the Secretary, to furnish the names of
    the occupants of such premises, or to give free ingress thereto and
    egress therefrom to any duly accredited representative of such
    Department or bureau or agency thereof, so as to permit the
    collection of statistics with respect to any census provided for in
    subchapters I and II of chapter 5 of this title, or any survey
    authorized by subchapter IV or V of such chapter insofar as such
    survey relates to any of the subjects for which censuses are
    provided by such subchapters I and II, including, when relevant to
    the census or survey being taken or made, the proper and correct
    enumeration of all persons having their usual place of abode in
    such premises, shall be fined not more than $500.