Actually Francisco I meant what I said, Assisted Opening knives are not legal here in Washington, and they are not legal in several states I have worked in the past few years.
You are right, there is a difference in the two, but the words the cops know is "Gravity Blade". If the weapon can open against gravity, it is not legal, or it falls into a grey area between the person carrying the weapon and the cop ( and how much of a by the book, do I want to mess with this guy or not ) situation.
I have a good friend who recently passed his probationary period with King County Sheriff tell me several of my knives were illegal based on his training IF the officer doing the inspecting wanted to be a hardass about it.
That is one the reasons that the Microtech CMTX5 was such a hit with Internet Knife Collectors. It opens like any normal folding pocket knife. Or, it has a built in spring that will launch it in the blink of an eye. Unless you know how to use the spring, it's a normal knife. Good luck finding one of those around these days though. Unless you are looking in my safe.