Even though you don't give out your password, you could still have someone trying to gain access to your account. Often times users overlook the obvious and use the same username and password on forums, game id, back accounts etc.
Lets say I use bigfatdummy as my username and then pwd as my password. I register on a fansite, this forum, the game, my email, work, etc with that same combination. I have seen many many times where a fansite looks up user id's and passwords in their DB and steal the accounts from players. One game Runescape is famous for this happening to players. People log into someones account and transfer all the items onto another account via the trade feature. The next day the original user logs in and they have been robbed. Even if you use that Password on another account its not hard for someone to make a connection. I play as User1, register as bigfatdummy and use the same password for both. Someone could easily make the connection between the 2 UID's and log in as you. I ALWAYS suggest using a password that is specific to the game you are playing. Something like PasswordWOW or PasswordCS is simple and you can add to that to make it very hard to crack.