You were simply detained, not arrested. I was pulled over once after picking up an oz. Cop asked what I had, handed it over, he detained me, checked the car, it was clean of anything else. Told me to continue on my way and apologized that video games wouldn't be as fun that evening.
Not decriminalized, but it's the lowest police priority here on the WC.
That being said, it's 2015... Why do we prohibit the use of a flower that has far less side effects than tobacco or alcohol? And why on earth do we continue to tolerate the low level drug turf wars it fuels when it can be taxed and taken out of their control?
Regulate, Tax & Restrict Access. Simple Adult Logic.