Garrison script

[Darviathar]

Playing England on VH/VH using 3.1.2. I selected the grand campaign, which I assume is the full set of scripts, including the garrison. I have taken Jerusalem with a crusading army and been besieged every single turn ever since. I am not getting any "extra" garrison units to help defend it. I know it is considered a "great" city, and from what I understand of the script, I expected extra units to defend. Scotland has taken York through siege. I got no units there. They have moved on to Nottingham, and it is under siege with no extra garrison units showing up.

How does this script work? I thought it would trigger when AI besieges player, as well as when I besiege an enemy city of importance.

[Lmagus]

It works only when:
You besiege AI city/castle.
AI besieges AI city/castle.

[Lord Finga]

hm, does it really also work for AI vs. AI? thought it has been canceled for this constellation, but maybe this was in another mod...