Right now, we are discussing changes to the rules, aren't we? But what's the point of creating rules that will initially contain loopholes for military tricks/cheating?
1. Should the organizer indicate which battles, in his opinion, are key before the start of the tournament?
An experienced player can, with a high degree of probability, suspect obvious cheating even in the final, and detecting it with save files from the end of the game will be close to 100%.
2. Does this mean that all intermediate battles should be played without losses by default?
What is a "routine" battle anyway? Is a single conservative unit a "routine" battle? It depends on what army I'm going to use!!! The same applies to dividing battles into long/short ones. And this approach applies to each battle.
Changes to the rules should eliminate the use of cheats in all "competing groups."
But there is, in my opinion, an effective proposal.
Currently, the top players are checked, and the organizer makes the selection. It could be made mandatory to check a certain percentage of participants in addition to the winners. The participants to be checked are chosen randomly.
It will be scary to cheat because you become a cheater once (just like a traitor). It will be VERY difficult to restore your reputation.