From David S. Bennahum’s “Hope You Like Jamming, Too” (Slate):
…innovative industrial spies, who have several neat new tricks. These days, a boardroom Mata Hari can purchase a specially designed cell phone that will answer incoming calls while appearing to be switched off. In a business meeting, she could casually leave her phone on the table while excusing herself to go to the bathroom. Once she’s gone, she can call the phone she left behind and eavesdrop on what the other side is saying in her absence.