random mobile phone searches in Sydney

I understand the role of SMS messages in fanning the flames of the riot and reprisals in Sydney, but I wonder, isn't this going too far?

Jane, from Coogee, was surprised to find three police on her bus asking to inspect mobile phones. Each took a phone at random and scrolled through messages for five or ten minutes. Everyone obeyed. "The people were perfectly friendly about it," she said. "I thought it was a bit weird and a breach of privacy. But I didn't say anything. Nobody did."
[Australians are an obedient people - but for how long?, Sydney Morning Herald, 19 December 2005]