I posted in Kesh's topic but figured i'd post it here as well.
The solution is to turn the exploit into a feature. Locking down your own villages should be allowed but with increased penalties.
Already there is the penalty of your troops being locked down. In the Dusturil case the Hospitallers/Occitans could have marched straight past the 1000 locked Fallen troops and instead attacked the reinforcing Fallen army 3000 vs 1500 (ish). If I had to pick between attacking 1500 troops in Dusturil or attacking 1500 troops in a random field I know which would have picked and would have seen the locked 1000 troops as a blessing
. A bit of intelligence on the Hospitaller/Occitan front could have seen an even better outcome for them without all this drama. Maybe they could have even gained some pride in the fact that they don't need the Devs to fight their wars for them.
Added to this is the already existant "Loki you are a scumbag" penalty. Attacking your own village is not the best way to look good and make friends
On top of these however I propose that all crafting, recruitment and selling of goods should be suspended during any village attacks. This means villages under attack are no longer profitable which should increase the penalty sufficiently to make clans think twice before using the attack your own village feature.
There does need to be a transfer village button though with a 1 week cooldown as obviously it is a little unfair to suspend production if you are just trying to transfer ownership.
This is by far the simplest solution as it requires no policing or punishments at all!!!
Poll