I can attest first hand to what you are talking about. I remember when I was a student driver. I was caught speeding. Not deliberately. It was my third hour and the police pulled me over. My instructor was on the passenger's side and after showing him my learner's license and I asked him to provide me with the documentary evidence that I was speeding. He said he used his judgment and concluded that I was speeding. I said I was not and that if that is the case why not give me a warning or give me some demerit points.
He said no, that is even after my teacher asked him to provide the evidence. In court, while I was cross-examining him, the judge kept cutting me off, and speaking on his behalf. At one point he told the judge that he had evidence that I was speeding. The officer then reached into his pocket and took out some document he then gave to the judge. I was not allowed to see it, and he made his ruiling based on that.
So, I can attest to an unfortunate encounter with the police. They are making their quota and following orders as they say.