Sirion and their allies used the "archer only" attack tactic during the assaults on Oligarch.
Note that there were both infantry and archers defending the city. Approximately 10k of each as I remember.
They would attack in one turn with only archers. Five realms worth of archers so it was 10k or 20k worth of archers. Since there were no infantry units at all, the defending infantry would charge out on turn 1 and get slaughtered by the attacking archers. The defending archers would win the battle in five or six turns, maybe eight, and do heavy damage to the attackers, but the infantry were all scattered.
And militia units don't usually rally immediately, so there were a couple turns where the entire infantry defensive line of the city was gone.
So the next turn Sirion and their allies would attack with what archers were able to rally (maybe 5k or 10k survivors) and their 10k or 20k infantry deploying as far forward as possible to avoid as many archer rounds as possible while they closed with the walls. With little to no infantry to man the walls, the infantry would storm the walls and engage the defending archers in close combat, thereby wiping them out as mass infantry charges always do to archers.
Note that the walls and defenses of Oligarch could handle 20k or 40k attacking force and had done so multiple times. There were enough infantry to repulse their infantry from the walls, and enough archers to kill the enemy at range. The "archer only" attack was designed purely to suck the infantry out so they could be immediately slaughtered on the field rather than holding behind the walls while the archers dueled.
That tactic, and that tactic alone, made holding Oligarch impossible and resulted in the end of Oligarch as a kingdom. Short of that tactic, Oligarch was holding its own with support from the Southern Alliance.
The issue is that any intelligent infantry would have stayed behind the walls and let the defending archers take out the enemy archers rather than charge out of the walls and get cut down. It's a stupid tactic, especially for a turn one action before the attackers have been softened up. I can see the idea behind the defending infantry charging out after there has been a mass infantry battle at the walls...after the attacking infantry have been shattered, and it is time to finish the attacking archers that have been dueling with the defenders the entire battle. But as a turn one tactic, for the defending infantry, to charge out against a fresh and dominant archer-only force when there are defending archers that can kill them in a few turns seems just utterly stupid on the face of it.
And a case could be made that purposefully planning attacks like that, designed to trigger that particular part of the code that sends infantry out when there are no attacking infantry, could be an abuse of the game code.
