Ill put this forward as an example.
Driving down a road in the 33. I was doing 80, cop comes up behind me *pwooo* yay my face drops. (Not condoning speeding, it was near 11pm and I've just been driving for 2 hours, just wanted to get home)
Cop pulls me up,
Me: Good evening sir
Cop: Any reason why you were speeding
Me: No sir, just want to get home
Cop: license (handed over)
wait for about 2 minutes
Cop: (hands me a fine for doing 10 over) Have you got a engineering certificate?
Me: For what sir
Cop: For your wheels, exhaust and that gauge
Me: No sir, wasnt aware that I needed one for those modifications (I was truelly unaware)
Cop: We will have to get that checked out
Me: Ok (poker face)
Cop: But I'm a bit busy tonight (cop gives license and fine and walks away)
Bottom line
Yes Sir No Sir May I have another Sir