In my experience, the only risk and proven danger are sales people. I've seen and met many former sales people whom developed relationships with their customers

In my experience, the only risk and proven danger are sales people. I've seen and met many former sales people whom developed relationships with their customers and then one day just quit their job and went into business of their own, with a lot of their former employer's clients as their new customers. I doubt there is anything anyone can do about it as this is about personal relations and the only defence could be to never allow one customer to be handled by a single account manager so there cannot be personal relationship developed. But on the other hand, will such customer feel good doing business with such a company? It might just be one of those things that just is what it is and will never change.