I think most of us are guilty of coming to a 'rolling' stop at 4-way stops... (not red lights, but intersections of two low-traffic streets). If I can clearly see a block in each direction to the left and right, I'll slow to about 10kph, ready to unclip my left foot with hands on the brakes, and pedal through.

I wouldn't do it in front of a cop, that's just tempting fate. you never know how bored the cop might be.

In vancouver there's a T-shaped 3 way intersection directly in front of the police motor pool parking lot entrance, with 3 stops signs. people roll through it at moderate speed on their bikes all the time, I've never heard of cops giving them trouble for it.