Corrected entry: In the beginning of the movie at the shooting range, all of the shooters are wearing earplugs, but none of them are wearing eye protection. No one ever is allowed to fire at a legitimate range, let alone a Police range, without wearing eye protection. Later when KC goes to the range alone, he has no ear or eye protection. This is possible since he was alone and angry about his father's murder, etc.
Corrected entry: What exactly is Macko arrested for at the end of the movie? They never say what the charge is. I suppose it relates to his investigation of Gavilan and Calden, which was meritless, but I can't think of any specific criminal charge to apply there. Perhaps subordination of perjury, since he made a deal with Lolita Davidovich to testify that she had relations with Gavilan? But then, he'd have to have known that that was untrue, and the cops would need proof of this to arrest him, which was not indicated at all in the scene. They just show up and arrest him.