There have been a few discussions about whether Hertz tracks where you picked a car from at Ultimate Choice locations, mainly from Gold/FS members wondering if they can take a car from PC.
After seeing several Hertz employees park cars in PC and walk over to a keypad, I went to see what it was.
https://imgur.com/a/5DE08eW
It looks like it's the same system they use for specific car reservations (i.e. go to this space number), only they're noting what car is in what zone. I don't know if all locations use it or pay attention to it, but the system does exist.