Or are there ghost containers on ships, which are filled with drugs and not part of the manifest, that an automated system would flag but people with greased hands know to let it through?
Just divert the container to an area without cameras for a few minutes, pop it open and remove the kilos.
In a manual world, nobody notices that the container takes 15 minutes longer to reach the storage area.
In a manual world, nobody notices that the container suddenly became 100lbs lighter.
In a manual world, nobody notices the GPS trace showing the container going behind the warehouse where the camera coverage is spotty.
https://www.occrp.org/en/project/narcofiles-the-new-criminal...
On the other hand, if there aren't supposed to be humans around it's a lot easier to spot people who don't belong: that would be literally every single human.
The second season of The Wire (https://en.wikipedia.org/wiki/The_Wire_season_2) covers this, as they track containers that come off a ship and end up in The Stack, and never make it onboard a truck (at least according to the tracking system).