What's funny is that when I e-mailed WDFW, and explained exactly what it was that I would be doing, they told me it was illegal.
"Thank you for contacting WDFW. As the other part of the regulation states it must be visible and exposed to the weather. So according to one of our sergeants and one of our officers, the things that you refer to would render them not visible and also no longer exposed to the elements. So, the answer to your question is no, you may not cover it with a “gun condom” or a piece of duct tape.
They're absolutely wrong, based on the WAC. That being said, you may have to take a ticket to court to prove it.