Please consider adding a premium item of any kind that will remove/unlearn/grey out the warfare talent.
Warfare guild tech is the only tech in the game that has a drawback. Everything else is positive/neutral
There are many reasons why the guild may want that tech gone. The guild can change policy, the guild roster can change, the talent could be researched by accident...
Obviously turning off guild warfare should not be simple. It is not merely the matter of diamonds, because then some guilds can get the tech, win a war and revert back to peace, becoming untargettable. So in addition to the scroll itself the guild must show its commitment to peace by not waging wars for a certain amount of time (at least one month but can be more) and by paying in other resources (gold, knowledge, soul shards, guild energy, guild tokens).
Right now warfare is irreversible, and it can be an infinite punishment for the guild and everyone in it.