In case anybody wants it in official writing;
"TITLE 18, PART 1, CHAPTER 33, Sec. 701. - Official badges, identification cards, other insignia
Whoever manufactures, sells, or possesses any badge, identification card, or other insignia, of the design prescribed by the head of any department or agency of the United States for use by any officer or employee thereof, or any colorable imitation thereof, or photographs, prints, or in any other manner makes or executes any engraving, photograph, print, or impression in the likeness of any such badge, identification card, or other insignia, or any colorable imitation thereof, except as authorized under regulations made pursuant to law, shall be fined under this title or imprisoned not more than six months, or both
TITLE 18, PART 1, CHAPTER 33, Sec. 716. - Police badges
(a) Whoever -
(1) knowingly transfers, transports, or receives, in interstate or foreign commerce, a counterfeit police badge;
(2) knowingly transfers, in interstate or foreign commerce, a genuine police badge to an individual, knowing that such individual is not authorized to possess it under the law of the place in which the badge is the official badge of the police;
(3) knowingly receives a genuine police badge in a transfer prohibited by paragraph (2); or
(4) being a person not authorized to possess a genuine police badge under the law of the place in which the badge is the official badge of the police, knowingly transports that badge in interstate or foreign commerce, shall be fined under this title or imprisoned not more than 6 months, or both.
(b) It is a defense to a prosecution under this section that the badge is used or is intended to be used exclusively -
(1) as a memento, or in a collection or exhibit;
(2) for decorative purposes;
(3) for a dramatic presentation, such as a theatrical, film, or television production; or
(4) for any other recreational purpose.
(c) As used in this section -
(1) the term ''genuine police badge'' means an official badge issued by public authority to identify an individual as a law enforcement officer having police powers; and
(2) the term ''counterfeit police badge'' means an item that so resembles a police badge that it would deceive an ordinary individual into believing it was a genuine police badge"
..and if that's just the police, I'm sure the Secret Service isn't going to be any more forgiving. Even so, I'm not sure convincing your buddy he's in trouble is considered a defense by the "recreational" clauses listed.