Characterizing EA's legal counsel as "passive aggressive," this Games Industry International report details how one of the world's largest publishers keeps former employees from sharing trade secrets with new employers. The report uses correspondence from Electronic Arts to ex-employee Ben Cousins, who served as the company's general manager for its Easy Studio. EA's counsel keeps tabs on former employees long after the leave the company in the name of protecting EA's proprietary and confidential information.
"We understand that you recently accepted the employment as General Manger of ngmoco Sweden," states the correspondence. "EA is seriously concerned about the possible solicitation of its employees and the possible misuse of protected intellectual property and trade secret information by you and ngmoco in violation of your continuing obligations to EA, and we want to both remind you of your obligations to respect EA's confidential and proprietary information, as well as EA's relationship with its current employees, and inform you that we will take action if we discover past or future breaches of you obligations."
The letter goes on to list "non-solicitation obligations" that it claimed Cousins could not do for six months after leaving the company.
These "non-solicitation obligations" included not speaking to EA employees, interview any current EA employee, provide any information relating to any EA employees, and use any EA information in order to draft job descriptions, recruiting materials, or set compensation for jobs.
You can read the rest of the tale here. There's no doubt that many other former employees get correspondence like the above example long after they leave the company.