Guessing there hasn't been an update yet on permissions for co-players?
As it currently stands, to change a password on an account you have to get a link sent through to the account holders email and change that way. However, if you want to change the email address this does not require a link from the email. Obviously, if anyone has access to the account they can hold it hostage.
W47 - Early game Rocket Man had a co player put on the account due to inactivity. After days, the email was changed and tribe disbanded. Mellowfax suggested this would be looked at (but not promised) in the future to prevent any accounts being able to be taken prisoner.
W47 - After this first event, the Murena account was taken hostage by a disgruntled co-player (Jack Lame) and force internalled as gifts to the enemy.
I know it's in the rules about this that accounts are players responsibility, but this is a loophole which is constantly abused.