The point is, it wasn't a serious matter, even if it was strange because of the way Crystal was dressed. It was nothing more than a public intoxication incident at 1 am. Shelton probably figured she was just another drunken hooker down on her luck who drank too much and got put out of a car by some john. It happens all the time. The point is, it wasn't a serious matter at the time that required an investigation so there was no reason to hassle Kim - just a public intoxication incident.
Cops get calls all the time to deal with drunks - all day long - starting in the morning and escalating at night.
Have to remember Kim didn't call the cops, the security guard did. How often do drunken hookers wander the streets? I can't believe the cops didn't run Kim's plates..unless of course they knew Crystal and/or Kim already.