Spring assist folding knives don't meet the NY definition of a gravity knife even though they are easier to deploy than many thumb stud knives. They can be purchased in the city.
Courts have interpreted that to mean that any knife that can be opened with a “wrist flick” — a movement something like what a fan dancer might do — qualifies as a gravity knife. A long list of court cases have turned on exactly that question, which seems straightforward enough."
I think spring assisted folding knives do meet this definition, and the article also does mention many folding knives sold in the city also meet this definition