"As always, should you or any of your Walmart Force be caught or killed, the Secretary will disavow any knowledge of your actions."

A public relations officer linked to Walmart posed as a journalist at a press conference held by a labor group highlighting tough working conditions in the warehouses that supply big retailers. 

Stephanie Harnett, a publicist working for Mercury Communications, which has been retained by Walmart to assist in its effort to open a new store in the Chinatown area of Los Angeles, claimed to be a student journalist called "Zoe Mitchell" when she turned up at the event on 6 June.

She then spoke to and recorded an interview with an activist from Warehouse Workers United...

The subterfuge only became apparent on Wednesday, when Harnett turned up at a different event and this time used her real name. She was spotted by members of WWU who recognised her and were stunned to see her handing out Mercury business cards with a completely different identity.

Walmart moved to distance itself from her actions on Thursday, and Mercury said neither it nor the retail giant had "approved, authorized or directed" her actions. It said she was no longer working for the firm. (more) (audio from the disclaimer experts)