I've been there, a half dozen times or more. It doesn't matter whether the cops might lie, or if the cop is friendly (which is a tactic), or whatever. If the officer demands ID and all you're doing is carrying openly- ask, "Am I being detained?"
If no, politely wish him a nice day and walk away. I've done that more than a few times, and that was back when OC was a little more dangerous than it is now.
If the officer says yes, that you are being detained, then ask, "For suspicion of what crime are you detaining me?" After all, there is a chance that the officer stopped you completely regardless of your OC. If so, stonewalling would not be your best choice. This is rare but it happens.
If the officer doesn't answer your question then you should realize that he knows he's on thin ice. He is trying to get you to start talking, and he doesn't care what you want to talk about, just as long as you start talking. Once you start talking, debating, arguing, citing RCWs or case law, or flashing pamphlets, you have consented to the encounter. From here on out you have no case against the officer if he does something questionable- because YOU volunteered to talk to him.
You can find, if you look hard enough, some horror story about an officer or officers screwing up, but if you insist on living based on those instances you're better off not carrying a gun at all.