How to stop rivals from raiding your talent (using fair means or foul)

"David Levine, a law professor at Elon University, suggests that company executives work with IT staff to spot irregular computer use, which can flag things like flash drives going out the door. He also recommends other internal controls like limiting the distribution of sensitive documents to ensure information doesn’t lose its legal status as a trade secret. Finally, Levine says exit interviews can be an important tool to detect whether an employee’s departure may be part of an early exodus to a competitor."