Here is a good story that I found from the Blog Planning Startup Stories.

Helping the Competition?

I have to agree that you never want to help build your competition even if they are your friends or relatives. Now, if we took this case and said the guy was starting a restaurant, I would gladly help in that case.

Something else you have to consider when you have employees, are you giving them the information needed to start their own business and compete against you? I had an old boss who was petrified of his employees starting their company (despite the extremely high start up cost related to the industry).

The best way to try to prevent this from happening is to treat your employees like gold and with respect. It wouldn't guarantee that an employee wouldn't try it, but the closer you are to your employees, the harder time they would have trying to compete against you.