Have a lool at the Victoria Coach Station plan PDF - as you can see there are separate departures and arrivals sides of the station. I think that theoretically anyone meeting an arriving passenger is supposed to stay back behind the glass wall and not venture out onto the 'roadway', but in practice I don't think there's any real control of this. But that's not an issue anyway - arriving passengers all get off in the same place and are channelled along the same exit route - see the plan, they all come through a door in the corridor where there minicab booking desk is marked.

The plan also shows timetable screens - I don't know whether any of these show anything along the lines 'real time' information (I'm don't think National Express has anything set up like that, not yet at least) - but I'd imagine they should at least show which coaches have actually arrived.