"I have a theory on how they smuggled the banner in. They rolled...

"I have a theory on how they smuggled the banner in. They rolled it up, put it in a bag, and the bags of audience members aren't manually searched."

Reaper, I heard a lady interviewed on radio who was in the audience at Q & A and she said that she couldn't understand how they got the banner in because everybody's bags were searched on the way in, she also claimed to have been frightened during the demonstration.
It would appear that there had been collusion by someone at the ABC with the protesters for them to get the banner in and then to be able to sit as a block on the balcony from where they could unfurl their banner.