When I tried that move in Zillions-of-Games, it didn't seem to give me any advantage. The computer responded with Cavalier g8-h6, which attacked my Cannon, provided protection for i7, h7, and f7, and made the Cannon unable to attack the Paladin on g10. From there, attacking the Marshalls would be pointless, because the Cavaliers in front of them could get out of the way by moving backward. Attacking the Nightrider doesn't do much good, because its value is about the same as a Cannon. Attacking the Paladin doesn't help because it can move away, and attacking the Queen doesn't help, because the Nighrider can block the attack on it.
When I tried that move in Zillions-of-Games, it didn't seem to give me any advantage. The computer responded with Cavalier g8-h6, which attacked my Cannon, provided protection for i7, h7, and f7, and made the Cannon unable to attack the Paladin on g10. From there, attacking the Marshalls would be pointless, because the Cavaliers in front of them could get out of the way by moving backward. Attacking the Nightrider doesn't do much good, because its value is about the same as a Cannon. Attacking the Paladin doesn't help because it can move away, and attacking the Queen doesn't help, because the Nighrider can block the attack on it.