The Balmain hate for Souths goes back to 1909, where as a sign of protest both Balmain and South Sydney were to not show up for the Grand Final because it was placed as a curtain raiser to a international Rugby Union match. Souths turned up, kicked off and place the ball over the try line without Balmain being there. The referee then awarded that Balmain had forfeit and Souths won the premiership. Souths maintain to this day that there was no agreement between Balmain and themselves.
Wrong.
No agreement was made.
The final was not to be a curtain raiser for a rugby union game.
It was to be the curtain raiser for a hastily scheduled 4th Wallabies vs Kangaroos game. The third game had a small crowd and the NSWRL needed more money to repay James Joynton-Smith for providing the funds to 'buy' the Wallabies players.
They used the final as a drawcard, but it meant the final would have to start an hour earlier.
Balmain protested because it meant some of their players would not be able to get to the venue in time after finishing work for the day. They used the exhibition game as an addendum to their protest.
Balmain hated Souths since then over rumours that an agreement had been made.
Souths hate Balmain for the 1969 Grand Final.
To prove that no agreement had been made, the NSWRL had during the week asked all first grade players to be at the ground with their playing gear as a combined city team would be assembled on the day to play Souths if Balmain went through with their protest.
Souths played this side and won, after they had kicked off and scored a try against no one to claim the title by forfeit.