Ashcroft v. Al-Kidd
Justice Ginsburg, joined by Justices Breyer and Sotomayor, wrote that it was "uncertain" just how powerful the Material Witness Statute was.  For example, she/ questioned whether a "law-abiding citizen" who was not suspected of wrongdoing could be sent to jail if he saw "a crime during the days or weeks before a scheduled flight abroad."  Ginsburg, Breyer, and Sotomayor were also concerned about how al-Kidd was treated in jail.  The Court did leave al-Kidd with the right to sue his jailers for mistreating him.