I thought it was policy to trash any existing characters if you became a CCP employee?
They freeze the account and you're not allowed to associate with your former friends in EVE in obvious ways like forums and the like. You're allowed to create a new account and fly with that, but can't go anywhere near sov warfare, 0.0 politics, or your old mates in EVE. If and when you are no longer a CCP employee your account is unfrozen and given back.
This is my understanding anyway.
There is actually a duration on it ... after a while (six months?) they unfreeze the main account and you can play it (even as a CCP employee)
But you aren't allowed to be very vocal in player community/forums/rage etc and should be obviously running a player corporation.
(Assuming nothing has changed in the 3 years since I met their internal affairs people) - I think the point is to make a clean break when you start the job and if you keep your nose clean and play nice you do get your original character back for usage - would be a bit of a deal-breaker for many otherwise