Lunch at the Labs

Much has been written about the HP spy scandal where Hewlett Packard spied on it's board members and members of the press to catch those who leaked confidential information. One thing never mentioned and what I do not understand is why a board member would use his home phone (or any phone that could be traced to him) to divulge information that he did not want connected to himself. How hard would it be to use a public phone or even an anonymous email account from a public terminal?