Proving that (a) I never get close to players during games, and (b) my TV is quite small, I have only just realised that Geelong wear white and navy blue guernseys, rather than white and black. I checked the other teams, and found a similar affliction with Adelaide and Melbourne. All this is good news, because it means that I can update my footy charts with unique colours for every team. Collingwood and Geelong are no longer twins, and neither are Essendon and Melbourne.
When I get a chance I'll update my historical charts with these corrected colours too.