This has been used before to protect treasures/vp. It's a good way to protect treasures and vp in the key moment of the server, like the end day. An off duke can do this after using his army, like on com3 now. Some players know how to exploit TK rules, and others learn and adapt, or leave the game in disgust.
The usual tk response is nothing, they just ignore the situation. This is wrong, the answer should be strong and against this kind of exploit.
It seems TK is a game won almost exclusively by cheating and exploits. Multis, bots, timed bans, api, bugs that show where armies/heroes/catas target/go... it's not worth spending and getting too involved.
What do you think, should this leadership strategy i.e. getting banned to protect treasures/vp result in a punishment for the kingdom, such as treasures/vp loss?