Is San Diego really Oakland South?

Each year, the Chargers/Raiders games are always big games because of the rivalry between the two teams. There's always alot of talk among the Raider fans about how San Diego is Oakland South because the raider fans flood the Q when they go down there. If San Diego is really Oakland South, then that has to make you question the loyalty of the charger fans. I personally think that this is sort of true, but not really, based on my experience at one of these games. I just want to get your guys' opinions on this