I have mixed feelings on this topic. In the past 2 weeks I've spent a couple of evenings in Cambridge (urban riding and lots of commuters, though mostly in designated bike lanes). Frankly I have never seen such blatant disregard of the law. Going through red lights, zipping through lanes of traffic, and no lights at night. And this is in a city that actually tickets cyclists. I hate to be seen as anti-cyclist, but this is one reason I don't ride in the city. The cars react to the riding and vice-versa, and everyone is angry, which is a recipe for disaster.
My son (the one who is not a cyclist) recently started riding the mountain bike we handed down to him around the city, as he realized he is a skinny out of shape person. He called us to ask why all of the other riders were going through lights and was this OK? We taught him the rules of the road a few years ago when he rode to a summer job and he was following everything we taught him last week. We told him to keep following the law!