Also, not really sure what measures you can take to penalize zerging, but the group cap of 5 didn't stop bigger groups in the slightest with towns. Going to a conquest point with 5 is just screaming that you don't really want it and that group of 10+ will be there shortly. Again, not sure what can be done to stop it, but it's definitely disheartening to 10 or more inc on your group.