Originally Posted by
gobluetwo
Upon reading the title, I thought this was going to be about airports checking your license plate when you exit the parking lots. They do this at ORD, which I always thought was weird. When I first moved to Chicago and had an out-of-state plate, they'd always ask what state it was from because it wasn't showing up clearly on their monitors. Total aside, but anyone know why they do this?
Lots of reasons, it validates the entry exit time on the ticket (in Newark for example the plate reader displays the total owed before you even stick the ticket in the machine). This way you can't really use a swapped ticket and pay for one day when your car was there for weeks.
It provides a data point for them to search the entry/exit images should the owner of the car come back and it's gone because you stole it.
It can prevent somebody from swapping plates of stolen cars at the airport if the ticket does not match the entry plate and the exit plate scans.
In some areas, they can also connect to external databases, and do things like boot you for unpaid tickets, etc.
Some airports employ the vehicle mounted scanners too, and can tell for example if a car has been there too long
Employees who should not be in the general parking areas can be caught.