We'll, I don't live there, but I've had family living in Colorado all my life and have visited there nearly every year of my life. My daughter did her graduate work at CU-Boulder and lived in Boulder and Longmont for several years afterwards. I have a cousin in law enforcement in Denver. I've seen people smoking up on the street in Boulder, Denver and various mountain towns. Conversations with my cousin and some of his friends is how I know that law enforcement has long felt that they had more important fish to fry than small-time users and growers. (Actually, they feel that way here in Wisconsin, too. I heard that directly from a DOJ special agent a number of years ago. They'd rather worry about the people who are cooking meth and selling heroin.)
Of course, lots more people don't smoke up openly, but keep it inside their homes. You'd probably be surprised at who they are. I know some pretty serious Colorado pot-heads who hold down high-paying professional jobs, belong to the PTA, go to church every Sunday morning.....in other words, live completely normal and responsible lives....and also smoke pot on a weekly, if not daily, basis.