According to director Stephan Elliott, he took the three leads out in drag prior to the beginning of filming. None of them were recognized: Guy Pearce took the opportunity to be outrageously rude, Terence Stamp eventually forgot he was in drag and started hitting on girls, and Hugo Weaving got super-drunk and lay under a table for hours, tapping his finger in time to the music. This last detail was incorporated into the film in the hotel room scene.
When they are in the bar in Broken Hill, Old Shirl comes over and slaps her right hand down on Bernadette's. Then, in the next camera shot, it's her left hand.
When Mitzi and Felicia wake up the morning after they left Bernadette and Bob to get drunk, if you look at the shot out of the bus window of Bob and Bernadette, Bernadette's face is next to the cake. Once Mitzi and Felicia are out of the bus, Bernadette's face is on top of the cake.
Tik is practising their dance routines and he is wearing a green dress and he's got a cigarette in his hand. In one shot the cigarette is there and in the next, which is far away, it's not there.