Hi Tom,
Sorry for the delay in responding. I agree with your assessment regarding assisted openers. I suspect that the captain and chief are correct that many NYPD officers would consider an assisted opener a switchblade, even though the assist device is on the
blade, not the handle, and the NY statute defines a switchblade as "any knife which has a blade which opens automatically by hand pressure applied to a button, spring or other device
in the handle of the knife." N.Y. Penal Law Sec. 265.00 (4) (2005). (emphasis mine)
For what it's worth, as a LE trainer I've spoken with a number of officers over the years (including a few NYPD folks), and their opinions on knives cover the gamut, from very knowledgeable and informed of the laws in their jurisdictions, to fairly uninformed, to misinformed. The problem with assisted openers is, to an uninformed or misinformed officer, the dramatic opening of such knives looks mighty "switchblade-like", and might lead him/her to make an arrest for a switchblade violation. I concur with your NYPD friends that many NYPD officers might make that arrest, although I also agree that arrests often result from more than simple knife possession, i.e., there is some other charge, such as brandishing, disturbing the peace, disorderly conduct, etc. (depending on the jurisdiction).
Even if the person arrested isn't ultimately prosecuted, or is prosecuted unsuccessfully, that person now has an arrest record (and maybe a hefty lawyer's bill) for a weapons-related offense, which can lead to adverse consequences or complications on a wide variety of life / career choices in the future, such as firearms carry permits, certain professional and business licenses, etc. Of course, adverse consequences and/or complications on such permits and licenses are much more likely to attach to actual convictions, versus "mere" arrests, on weapons-related offenses (in this case, fourth-degree criminal possession under N.Y. Penal Law Sec. 265.01.)
Finally, as you noted, such knives may potentially also support a gravity knife charge under N.Y. Penal Law Sec. 265.01, due to the NY statutory definition of gravity knife under Sec. 265.00 (5). Since practically any folder without a closed-position lock can be opened by centifgual force, and application of such force applied while holding the blade will often open a folder that's hard to open with centifugal force while holding the handle (and the NY statute does not appear to limit application of such force to the handle), my suggestion to those who carry folders, whether assisted opening or not, is to make sure the folder's pivots are sufficiently tight (obviously not so tight that you need two hands, a vise and a crowbar with a gorilla jumping up and down on the other end to open

) to minimize the ability to easily open with centrifugal force. I think that's the best you can do, unless you have a folder that has a closed-position lock, which, ironically enough, is often found on automatics (switchblades)!