[javawizard]

As others have commented, it would be relatively simple for airports to deploy ANPR[0] to detect cars picking up passengers at the curb more frequently than an average person would be expected to, at which point they have the usual trespassing remedies at their disposal.

[0]: https://en.wikipedia.org/wiki/Automatic_number-plate_recogni...

[fallingknife]

Aren't they public roads at the airport?

[khuey]

They're owned by the airport and there are restrictions on their use.