I was at the sheriff's station the other day recording and they told me to turn it off because it's not legal. However, it IS legal. Also, if recording takes an all party consent, then surveillance from the police squad cars shouldn't be legal.
That's the RCW for recording "private" conversations. It says consent is gained when one party announces it. No party can say "don't record me." They can only not talk to not be recorded. Focus on number (2) where it says "unlawful requests or demands" need not be announced if you record.
Just hide your recorder OR say "Am I under arrest?" If they say yes, use the magic words, "I am going to remain silent, and I would like to speak to my lawyer." Officers try hard to get you to admit to guilt so they can arrest you. Just shut up and keep the recorder rolling.