Probably not the best example, but I understand your meaning.
As an adult, I've been pulled over for faulty equipment(lights burned out), license plate displayed improperly, speeding, etc... there was never a time that I had enforcement interaction with the police that I didn't deserve. Each and every time, I told the absolute truth and off I went. The one time I did get a large speeding ticket, I absolutely deserved it. The one time I got a 5 over during a michigan state police action period when they were pushing for raises, I just rolled my eyes and paid it. I was over, so yes, I was speeding, but man, 60 in a 55? Oh well.
I've been on the receiving end of that exact scenario you gave a couple times in my youth. It did nothing to stop us from drinking again. We'd pour the beer out, drive off, and head to the liquor store again. Yes, taking advantage of a cop's good nature. Too many people did the same thing as us, drove off drunk, got in a wreck and killed someone. The cops get sued for letting the drunk go, and the cops finally learned you should never let a drunk go. It's not worth risking other peoples' lives, or their career, to do someone a favor.
I really wish the cops would have arrested me, or at least made my parents come out and get me. Maybe it would have knocked some sense into me earlier in my life. Stopped drunking in 1985.