Maybe they were familiar with the Mangum, but that has nothing to do with their approach to Kim AT THE TIME. Disagree all you like. but I know what I'm talking about. Thirty-two years in LE didn't fall on deaf ears. They thought they had a common drunk who was given a ride by a sympathetic person who wanted to get rid of her, nothing more. They had no reason to run Kim's plates or ask her for ID or search her car or ask her name or question anything about the situation. It was, at that time, a very minor and very common incident - a drunk in public call from a citizen. They happen all day long, and it wasn't sloppy.
If you call the cops about somebody being drunk or behaving strangely, you would not expect to have your car searched, produce ID, and be run for warrants. All you did was call about somebody in distress or being a nuisance. If a bunch of kids or some drunk are hanging out on your front lawn creating a nuisance, and you decide to call the cops, would you expect to be ID'd, run for warrants, and your house and car searched?
Absolutely! The initial cop on the scene evaluated the situation correctly - a passed out drunk who wouldn't get out of someone else's car. If Mangum had never cried rape, then Kim would have never matter.