text: Crucifixion was only reserved for treason in the case of citizens.  It was used on non-citizens for other crimes.  And Jesus being crucified to avoid a riot appears in all four Gospels.  Pilate normally wouldn't have cared what the Jewish leaders thought, but he was fighting for his political and possibly literal life. http://www.bethlehemstar.com/the-day-of-the-cross/pilate-and-sejanus/