If we just want to talk anecdotally , I can tell you I have been caught red handed on several occasions in my life.
Once with an OZ in an elementary school parking lot on a Saturday. No arrest. No hassle.
Once, having a cop literally jump out of the bushes on me as I was coming out of a cul de sac (ppl had been complaining the cul de sac was being inundated because of a misplaced sign. I made the incorrect turn and he was waiting for me. I literally exhaled a big ol hit as I pulled to a stop. No arrest, no hassle.
There are cool cops out there. Sometimes you have to be cool first and give them a chance to reciprocate. Not all do, and there are abuses, no doubt.