How Many More Undercover Wal-Mart PR Spies Have There Been?

Yesterday, Stephanie Harnett, a young staffer at Mercury Public Affairs in L.A. who was working on behalf of Wal-Mart, was fired after she was caught posing as a reporter in order to spy on a press conference of a pro-labor group. Did one young staffer go rogue? Or is this standard operating procedure?
