I completely disagree with this statement using WA state law. What is "properly signed"? 1) there is no WA state "gun signage" law. 2) Its a PUBLIC (assuming you mean private business open to the public) place. Anyone is allowed to be there while doing lawful business. 3) You are not trespassing by default in a public place (sign posted or not) unless you are asked to leave for unlawful reasons. If you refuse to leave, than you would be trespassing.
I, too, am unaware of any gun signage law in WA, but the anti-gun signage campaign is based on state and city trespass laws. For example, this is the sign used in a campaign in Seattle started in 2013:
http://monderno.com/wp-content/uploads/2013/08/Seattle-Gun-Free-Zone.jpg
The campaign was started by a local anti-gun organization and endorsed by Seattle's mayor. From what news reports I've read, these signs were being installed in all sorts of businesses in proggie Seattle, so I'm surprised to read here that some folks who spend a lot of time there have never seen one. Of course, the news stories I've read may have been proggie propaganda.
It's my understanding that if any appropriately sized sign is posted at an appropriate height within a given short distance from the entrance of a privately owned public accomodation, you, as a gun carrier, have been informed of the owner's desire to not have your gun on his premises, and if you do bring it onto the premises, concealed or not, you are then guilty of criminal trespass. Note that the municipal and state codes cited on the sign are trespass statutes, not gun laws.
It is my understanding that if you are made carrying a gun in such a signed establishment, you can be approached by the owner or one of his representatives and asked to leave. At this point it would probably be wise to do so, unless you are principled enough and brave, stupid, rich, or poor enough to be a civil rights martyr.
In hoplophobic Seattle, if made carrying it is more likely that the owner or his rep would call the police who would then approach you about your trespass. They would undoubtedly first ask if you saw the sign. If you were foolish enough to answer in the affirmative, I fear you would be admitting to criminal trespass, the consequences of which can be severe. If you deny seeing the sign you will be asked to leave. I suppose you could go to your vehicle, unholster your gun, and lock it inside (out of sight per WA law), and return unarmed to the establishment that just evicted you. But, returning armed at any time after a police encounter, which will presumably be documented, puts you at risk of arrest for criminal trespass if ever made there again.
The Seattle campaign was orchestrated to use trespass laws, as no gun laws exist for the anti-gunners to use. Whether it has worked or not I don't know, because, although I live in the same county, I don't spend much time in Seattle. I focus on national, not local, news, so I have no idea how this WA Ceasefire campaign has fared.
This would only apply to a private business open to the public. If we are talking about a truly public place, like a park, sidewalk, etc, than only the police can ask you to move on, or charge you with a crime (loitering, disturbing the peace, threatening, or whatever misc. charge to get you to comply.) Of course, all of this only applies if you exposed your firearm for some reason and someone wanted to make an issue of it. BTW, WA is an open carry state too, so you should be covered (depending on many circumstances) by accidentally exposing a firearm.
I agree that there is no gun legislation a municipality can impose to keep firearms out of public spaces not expressly identified under state gun laws, because state gun law prohibits municipalities from enacting any gun laws that are stricter than those of the state.
The only place in WA state where signs have any weight would be FEDERAL institutions (post offices, federal buildings, nuke plants, etc), non public space in police stations, jails, court houses, schools, and bars (or the portion of a restaurant reserved for a bar), and TSA controlled areas. Even then, the sign is only a reminder of what state law says. The sign itself has no weight. If the sign was not there, you would still be in violation, because you need to know the limits of your CPL. There is a mandated sign for federal property by federal law, but that has nothing to do with state law.
Sign or no sign, it's my understanding one may not possess a firearm inside a federal facility -- ie, inside a federal building. For example, I think I can drive onto USPS grounds armed and drop a letter into their drive-thru mailbox; but, I'm in trouble the moment I step foot inside the Post Office building while armed. Similarly, I can legally carry on National Forest and National Park lands, but if I enter inside a USFS or USNPS Ranger Station while carrying I've produced cause for a costly federal case against me.
Outside of those, you are free to conceal carry (with your CPL) wherever. Remember, as pointed out above, concealed means CONCEALED. That is what your CPL is for.
The only times I have gotten close to carrying in an area it is unlawful to do so is at a National Forest Ranger Station. I have concerns about carrying onto medical facilities, because the state prohibits carry in hospital psychiatric wards. While I have successfully avoided such wards to date, my physicians practice in medical buildings that are structurally connected to hospitals with such wards. While I assume I am free to carry throughout the interconnected facility, except on such wards, I have no desire to have a run in with someone who's interpretation of the law is not as refined and elegant as mine; but, more importantly, I have opted to date not to carry when visiting a physician, because one is often asked to disrobe during such visits, and there is too great a chance that the physician may subscribe to Harvard Medical School's pseudoscience about the supposed health risks associated with gun ownership.
