I don't have a full answer but what I observed is that there is always someone that is nearby and "in control".
The base I think works like this:
- you scan the passport
- you look at the camera
- your passport details & photo are sent to the control room with your live feed
- a guy looks at everything those details plus your immigration history and other info
- same guy decides to let you in or send you to a desk
This was particularly obvious in the old Gibraltar border where you could easily be the only person going through and so the agent had to do the routine just to let you pass.
The base I think works like this:
- you scan the passport
- you look at the camera
- your passport details & photo are sent to the control room with your live feed
- a guy looks at everything those details plus your immigration history and other info
- same guy decides to let you in or send you to a desk
This was particularly obvious in the old Gibraltar border where you could easily be the only person going through and so the agent had to do the routine just to let you pass.