He said the guy flew past him going 41 in a 30, while he had someone pulled over on the side of the road. That's incredibly dangerous for the cop and the person that's pulled over.
He was in his car, though. And if it was a 30 mph zone, it was probably just some lightly trafficed residential street.
I usually set my cruise control at 10 over and don't slow down when I see cops on the side of the road. Haven't been pulled over. I've literally passed cops on the highway when they were going slower than 10 over... and haven't gotten pulled over.
6 or 7 years ago I was doing 85 (20 over) late at night with minimal traffic. I was in the left lane. Cop comes up behind me doing about 100. I see him, but I can't pull over, because theres a car in the right lane. Most people would brake... but if it were me, that would just piss me off, because then I (the cop behind you) have to brake as well. Instead of braking... I figure, fuck it, braking now isn't gonna save me from a ticket anyway. So I just passed the car @ 85, and then pulled over.
At this point, the cop now just loiters in my blind spot, not passing. Probably running my plate or something. I'm still doing 85, and quickly coming up on some old shitbox doing 60. Again, I think, "meh" and signal back into the passing lane, in front of the cop. I pass this guy, and then signal back to the right-hand lane again. Finally, the cop just passes me and takes off.
Moral of the story: most cops aren't concerned with your speed if you aren't an inattentive douchebag.