Leadcounsel, it IS illegal to carry a concealed weapon into bars in the State of Washington.
As a rule of thumb, if you have to be carded to get in, or if there is a "No Minors" sign posted, do NOT carry your weapon inside.
In WA State, you also may not carry in:
Court houses
Police stations
Jail or correction facilities
Past the security checkpoint at any airport
Anywhere liquor is served as a primary function of the business, and
Anywhere where the business owner has posted that firearms are not allowed.
To the OP: I would have done the same thing myself--but I would not have gone and deposited my firearm at home. I just would not have entered; if someone asked why, I would have said, "Hey, I'm just not hungry right now--I'll meet up with you guys in an hour or so."