6 U.S. Code § 1104 - Immunity for reports of suspected terrorist activity or suspicious behavior and response
Any person who, in good faith and based on objectively reasonable suspicion, makes, or causes to be made, a voluntary report of covered activity to an authorized official shall be immune from civil liability under Federal, State, and local law for such report.
Any authorized official who observes, or receives a report of, covered activity and takes reasonable action in good faith to respond to such activity shall have qualified immunity from civil liability for such action, consistent with applicable law in the relevant jurisdiction. An authorized official as defined by subsection (d)(1)(A) not entitled to assert the defense of qualified immunity shall nevertheless be immune from civil liability under Federal, State, and local law if such authorized official takes reasonable action, in good faith, to respond to the reported activity.
Any person or authorized official found to be immune from civil liability under this section shall be entitled to recover from the plaintiff all reasonable costs and attorney fees.
The term “passenger transportation system” means an entity or entities organized to provide passenger transportation using vehicles, including the infrastructure used to provide such transportation.
The term “vehicle” has the meaning given to that term in section 1992(16)  of title 18.
This section shall take effect on October 1, 2006, and shall apply to all activities and claims occurring on or after such date.
 So in original. Probably should be “intercity rail passenger”.
 So in original. Probably should be followed by a comma.
 So in original. Probably should be section “1992(d)(16)”.
Subchapter IV, referred to in subsec. (d)(3)(B), was in the original “title XV of this Act”, meaning title XV of Pub. L. 110–53, Aug. 3, 2007, 121 Stat. 422, which is classified principally to subchapter IV (§ 1151 et seq.) of this chapter. For complete classification of title XV to the Code, see References in Text note set out under section 1151 of this title and Tables.