All TC has a attack line of sight, just ensure if the player’s unpacked TC gonna have an overlap with enemy’s attack line of sight area, if that is the case then the player cannot unpack. Also the speed bonus for all packed buildings need to be moved to feudal.
This only applies to player vs the enemy player, does not affect the player itself. If a player want, they can place 2 TC together.
Also a tile check can be done, can only unpack 8 tiles away from enemy TC