The main difference between the two is that false arrest requires an arrest, but, false imprisonment only requires unlawful detention. Example and Hypothetical Scenario.Unlawful Imprisonment in the First Degree is a New York criminal offense imposing harsh penalties on anyone who restrains another person. Law enforcement has the right to arrest someone only if there was probable cause. Fill out the complaint form, answering all of the questions completely. 'is a complete defense to an action for false arrest. Probable cause is a complete defense to an action alleging false arrest or false imprisonment whether brought under state law or § 1983. § 1983 and state law claims of false arrest, false imprisonment and malicious prosecution. Black's Law Dictionary defines false imprisonment as "A restraint of a person in a bounded area without justification or consent. Allowing yourself to be taken advantage of in the Nassau County legal system is a bad idea.