Whenever a foreign a tower or a keep is taken a message is displayed for the taker which guild has given up control of the taken structure.
This information is of little interest for the opposing realm, as they have no way of contacting said guild, nor do they have reason to.
If enemy forces take a tower your own realm owns a message like this is given out:
No information of the guild previously owning the structure is given, the only way to find out who had it claimed would be by accidentally not having updated the realm war map. It would be very useful for the defending realm to get the information of the guild previously owning the tower/keep to inquire for numbers of offenders.
Please print the message "XXX has lost control over (insert tower/keep name here)!" for both home and enemy realm.