False imprisonment is the intentional and unlawful restraint of a person by violence or threat of violence, and the defendant made that person stay or go somewhere against their will. It must be intentional in that the defendant meant to restrain someone. If a defendant were locking up a store, not realizing someone was still inside, and that someone was then stuck, it would not be considered intentional and therefore not false imprisonment.
Confinement or detention also constitutes unlawful restraint. It is unnecessary for a defendant to have a person locked in a cell, jail or prison to satisfy the element of confinement; a defendant need only use violence or threat of violence to falsely imprison that person.
Violence is any physical force that is greater than the force reasonably necessary to restrain someone. In other words, if a defendant only needs to hold a person by the arm to restrain them, but instead knocks that person down with a bat, it would satisfy the element of violence. The threat of violence is also sufficient to constitute the restraint for being charged with false imprisonment. That threat can be express or implied to the person that is meant to be restrained. For example, if a defendant told a person they had to sit in a chair and not move while pointing at a gun in his or her own waistband after that person had expressed that they wanted to leave, if that person then sat in the chair and did not move it would constitute false imprisonment.
Consent is a defense to false imprisonment. If one consents to staying wherever a defendant has told them to stay, it is not false imprisonment. However, this consent must be voluntary. As in the previous example, that defendant could not claim that the person consented to stay in the chair because the defendant implied shooting that person if they moved by pointing to the gun and telling them to stay put; the threat would vitiate any consent that the defendant could claim.
Another defense would be parental rights to punish their own children. A parent has the right to restrain his or her own children so long as the parent acts reasonably; because a parent has the lawful right to restrain their child it would not be considered “unlawful” restraint. If it is shown that that parent was unreasonable in their confinement or that that parent had the intent to endanger the health and safety of their child, they can still be prosecuted for false imprisonment.
Elements, crimes and defenses vary from state to state and within the federal system. If you or someone you know is charged with any crime, as always, you should consult a local attorney, licensed to practice in your jurisdiction and preferably one practicing only criminal law. You can always look for your local criminal attorney at http://www.crimelawyers.org/