18 U.S.C. § 1730

Whoever, not being connected with the letter-carrier branch of the Postal Service, wears the uniform or badge which may be prescribed by the Postal Service to be worn by letter carriers, shall be fined under this title or imprisoned not more than six months, or both. The provisions of the preceding paragraph shall not apply to an actor or actress in a theatrical, television, or motion-picture production who wears the uniform or badge of the letter-carrier branch of the Postal Service while portraying a member of that service.