To say the least, gravity knives are controversial in New York. Gravity knives are considered per se weapons and the mere possession of one is a misdemeanor or, if a person has a prior criminal conviction in any state, prosecutors have the discretion to charge a felony.
The criminal consequence of possessing a gravity knife is bizarre considering their wide availability. According to an analysis by the Village Voice, there were 60,000 gravity knife arrests from 2003 to 2013 in New York. While a federal lawsuit is pending on the application of the law, in People v. Parrilla, New York's highest court ruled that the prosecution does not have to prove that a defendant knows that he or she possess a gravity knife. That means that the knowledge element of the possession of a gravity knife is strict liability. Obviously, the prosecution does need to prove that a person knowingly possessed a knife.
At this point you may ask, what is a gravity knife? Under New York State law a gravity knife is defined as: "any knife which has a blade which is released from the handle or sheath thereof by the force of gravity or the application of centrifugal force which, when released, is locked in place by means of a button, spring, lever or other device." In layperson's terms, it is a knife that is opened by flicking one's wrist and the blade locks into place.
In the case of People v. Parrilla, in 2011 the defendant was stopped for a traffic infraction, patted down and a gravity knife was found in his pocket. (Of course searches are not authorized for mere traffic infractions, which is an issue that must have been litigated prior to trial.) Mr. Parrilla was arrested and charged with felony weapons possession for the gravity knife. At trial, Mr. Parrilla testified tested that he bought the knife at a chain retain store in New York City (stores have since ended such sales). Here the important part: he testified that he worked as a tradesman, used the knife on the day of arrest to cut tile and always opened the knife with two hands and never by flicking his wrist. In other words, Mr. Parilla had no idea that the knife he used for work and when stopped by police was illegal.
After the close of testimony the judge instructed the jury that, "A person does not have to know that the knife is specifically a gravity knife or that it fits the legal description of a gravity knife in order to knowingly possess it. The People are only required to prove that the defendant, with respect to the knowledge element, knowingly possessed a knife." After the jury deliberated, Mr. Parrilla was convicted of Criminal Possession of a Weapon in the Third Degree and was sentenced to 2½ to 5 years in prison. Yes, Mr. Parrilla spent a few years in prison for possessing a knife that he used for work and did not know was outlawed in New York.
While New York's highest court ruled that knowledge that a knife is a gravity knife is not required to secure a conviction, reforms considering gravity knives are long overdue. For example, New York City outlaws the possession of knives with a blade of four inches or more, though it is punished as a violation and not a crime. Interestingly, New York City's four-inch-blade ban comes with several caveats that appear to be absolute defenses to the law. The ban does not apply when a knife "is being used for or transported immediately to or from a place where it is used for hunting, fishing, camping, hiking, picnicking or any employment, trade or occupation customarily requiring the use of such knife."
It would make sense for the state to adopt New York City's approach, so, at the very least, people who possess a gravity knife for work--and have no intent to use the knife otherwise--may not be caught in the web of the criminal justice system and possibly spend years in prison. When a person is arrested and sent to prison for years for possessing a gravity knife that is genuinely used for work, the punishment clearly does not fit the crime.