well, for me it depends on the situation.
If it were a stop sign on Rte 38, or 73, I'd sure as hell
stop. If its a side street the slow to 5mph works for me.
I've run red lights, but only after determining that I couldn't trip the sensor.
As for the cop on the sidewalk, alot of them are replacing "walking the beat", it's not a means of transportation per se, but a means of patrolling the neighborhood.
I bother because for the most part it keeps me safe. I think that if we (cyclists) did more to ensure predictablity to motorists, and seem less likely to act like idiots we might get more respect.

Marty