Legally, cyclists are supposed to obey traffic laws. That seems pretty reasonable, but what do you do when you find one of those lights that only turns green when a car is waiting. There are quite a few around here--at least two on my daily commute.
I had been carefully riding through the red light if no cars showed up. But a week ago, a car came speeding through a light that had just turned red and came very close to hitting me. I could, at least for many of these lights, walk over and press the pedestrian button. It's a pain, but I've been doing that lately at one of the lights where cars only rarely show up.