Hi Michael,
I’m Charles Pitman, Product Marketing Manager for AutoVu™ at Genetec™. One way to avoid using a hotlist/ blacklist would be to monitor duration of stay, as you mentioned, and then generate reports based on a threshold duration (say 6 or 7 hours). You could periodically generate reports spanning a limited time frame (say 1 or 2 weeks, but this is only limited by your retention period for ALPR data) and see whether there are any recurring infractions. You would then enforce the rules (whatever that implies for your customer) and possibly add that License Plate to a unique hotlist of offending employees. This would alert you the next time they show up, and a warning can be presented to them upon arrival. We have seen this type of application often at malls and even some hospitals to prevent abuse in areas reserved for clients and patients, which are frequently convenient parking spots.
Our new gateless parking module, AutoVu™ Free-Flow, includes standard functionality(e.g. Free-Flow Reporting) that would allow you to generate such reports. You would set the convenience time to the parking duration beyond which you would like to be notified, and then use the reporting task to view recurring violations to identify license plates displaying employee behavior. There is also a dashboard (Free-Flow Monitoring) that allows you to monitor all infractions in real time. Other standard tools are included that will allow you to investigate specific vehicles after the fact, and use the data to discover the parking trends of cars in your parking lots.
If you would like any more details or information, feel free to contact me at cpitman@genetec.com.