this is serious stuff where lives are at risk but I can't help thinking of vehicle roundabouts and the human interpretation of what is correct
roundabouts: Situational awarness is required - what lane - where not to cross - when to go and where / / how to exit; (what direction - for some); etc
aircraft circuits: Situational awarness is required but there are vertical and horizontal dimensions, and speeds, heights, conflicting directions, etc
Both require correct human interpretation - radios will help a great deal (joining pilots can understand the likely circuit being used and who is out there using a radio properly) - but I think the human interpretation of what is the correct way to join is the big one