When HP’s ex-CEO Mark Hurd headed to Oracle this fall, his former employer sued him, claiming that by taking the job he put “HP’s most valuable trade secrets and confidential information in peril.” While HP ultimately dropped the suit, and Oracle promised in the out-of-court settlement that Hurd would agree to protect HP’s secrets, it’s unlikely that he will somehow wall off the part of his brain that is familiar with his former employer. HP’s lawyers know it; so do Oracle’s. So do most lawyers at major companies, where top hires from competitors are common and clever information-gathering on the golf course is a way of life.