The World's First Flash Mob?

Did the the world's first Flash Mob take place in 1838 at the Cascades Female Factory ( a prison and workhouse for female convicts) in Hobart, Australia? The governor of Van Diemens Land visited the factory and attended a service in the chapel. Entertaining the governor was the Reverend William Bedford; a morals campaigner whose hypocrisy had elicited the lady's scorn. Keen to impress the governor with a fine speech, the Reverend addressed the women from an elevated dais, then:

"the three hundred women turned right around and at one impulse pulled up their clothes showing their naked posteriors which they simultaneously smacked with their hands making a loud and not very musical noise. This was the work of a moment, and although constables, warders etc. were there in plenty, yet 300 women could not well be all arrested and tried for such an offence and when all did the same act the ringleaders could not be picked out."

This cheeky behaviour 'horrified and astounded' the Governor and the male members of the party. As for the ladies in the Governor's party, it was said, in a rare moment of collusion with the Convict women, 'could not control their laughter'. From Female Factories