In one of my games, China did something pretty clever, unintentionally, or not. He just camped warrior monks on his districts, and his other districts were underdeveloped so I couldn't send rock bands to them. It only worked because he had some random wonders that he didn't occupy. Should this be changed? Maybe they should work like religious units. This makes Rock Bands trivially easy to counter. Added to the high faith cost and RNG aspect of them, this pretty much means they only work on an opponent that is throwing the game.