Why did Customs copy the address book from a mobile phone owned by the wife of Michael Quinlan, owner of the Switched on Gardener chain? (Tony Wall - Sunday Star Times).
The incident has sparked concerns police are circumventing warrants by using Customs' sweeping powers to detain, search and take information from international travellers.
The Customs Act makes it clear that Customs can only use their powers to investigate offences under the Customs Act. While they're allowed to pass on information about other serious crimes to the Police, there's definitely no provision for deliberately collecting data on behalf of the Police.
See this article I wrote for more information about Customs and their rights to seize and copy digital data at the border.