I wouldn't think that should be a problem here if there is any sanity how the system is implemented. With a normal (short stay, long stay) parking lot it is expected that cars leave all the time. A thief breaking into your car and driving off with it, and you getting into your car and driving off with it looks almost the same visually.

Here cars normally leave by a robot picking it up and depositing the vehicle in a garage. Probably there is a vehicle entrance to the parking area for maintenance, but it would be weird to see a car leave through that. Similarly thiefs could cut a hole in the fence and drive through that but again, visually very distinct from a normal operation. Of course it still doesn't help if the security is in on it, but it would be easier to notice that things are askew for a competent security.

So that leaves us with the thieves somehow confusing the digital systems so it dispenses the car to the thieves. And that very much depends on the security of their digital systems.

Hence why I think it would be hard to secure a normal parking lot even when operated competently. But this has the potential if implemented well, to be much more secure.