From how I interpret the RCW, any fixed blade knife is illegal to conceal, but can be carried openly. Any length folder is legal to conceal. Kind of dumb, but those scary/evil looking black rifles... er.. uh... fixed blade knives can't be trusted.
Too confusing for this dumb old fart, if I am going to a place I have not been or seems to be a grey area for what I carry I contact them. Talk to head LEO that area get name when talked to tell them you will keep info with there name on your person and that's worked well for me.