Spring blade knives are illegal. This is the definition of a spring blade knife:
(2) "Spring blade knife" means any knife, including a prototype, model, or other sample, with a blade that is automatically released by a spring mechanism or other mechanical device, or any knife having a blade which opens, or falls, or is ejected into position by the force of gravity, or by an outward, downward, or centrifugal thrust or movement. A knife that contains a spring, detent, or other mechanism designed to create a bias toward closure of the blade and that requires physical exertion applied to the blade by hand, wrist, or arm to overcome the bias toward closure to assist in opening the knife is not a spring blade knife.
For those want to read additional sections this is a link to the Revised Code of Washington (RCW):
Please explain your logic.