One member of the group of waving the Chinese flag in Brendan's direction. He seems to have touched the flag or put his hand forward to touch the flag. The man with the group starting yelling very loudly "stop touching her". But it wasn't a desperate cry for help, it was very deliberate and forced in a way. He realized all of the sudden he could get Brendan in trouble.
The other members in the group were happily smiling in the background, obviously not bothered by this horrible "touch assault". When police came, the Chinese man immediately ran towards the police to be the first to tell his story.
So there seems to be some awareness that "touching" is not allowed here, but I think with a bit practice they might find out about Streisand effect and filming in public too