First off, I'm not a lawyer.
In WA, you do not have to declare that you are carrying, OC or CC to an officer unless they ask something to the effect of "Are there any weapons in the vehicle?" or "Do you have any weapons on you?"
Nor do you have to hand over your CPL if you are concealing unless demanded to do so by someone if the law requires you to. RCW 9.41.050 (1)(b) states:
"(b) Every licensee shall have his or her concealed pistol license in his or her immediate possession at all times that he or she is required by this section to have a concealed pistol license and shall display the same upon demand to any police officer or to any other person when and if required by law to do so. Any violation of this subsection (1)(b) shall be a class 1 civil infraction under chapter 7.80 RCW and shall be punished accordingly pursuant to chapter 7.80 RCW and the infraction rules for courts of limited jurisdiction."
Now, the fact that it says "...and if required by law to do so." means to me that there may be some other law regarding when an officer or "other person" may lawfully demand to see your CPL. I'm not sure what that may be.