From what I understand, switchblades are considered such if the knife opens by pressing a button or a release on a handle to then release the blade. Assisted openers are legal because you have to touch the blade (be it thumbstud, thumbhole, or flipper) and move it past a certain point before the spring takes over and the knife opens. It seems to me that the bi-fold probably falls under switchblade classification because although you're touching the blade to open the knife, you're not pushing the blade open. To open the knife you have to depress a trigger or button which is on the handle portion of the knife, thus classifying that as a switch on the handle and thus it's a switchblade.
Definition and legal issues aside, that is a very interesting knife. I wouldn't carry one, but it is a very unique concept. I like it.