Attacking undefended Cities or Factories

[SJE 1]

So, if someone foolishly leaves an undefended City or Factory (not a Bastion) on a planet (no other units present) and an attacker Advances onto it, what happens?

If enemy troops occupy a planet with my structure it's a contested area which provokes combat, however combat ends when there are no units or bastions left in the area, so do you go through a single Execution phase (presumably representing partisan resistance to the invading forces)? Play cards against each other and then the attacking force is likely to win unless very unlucky or small? Then with no native units in the city, you declare it victory and capture the city?

Also presumably can you play Reinforcement tokens to rush in some troops on the City side?

[Wh0isTh3D0ct0r 360]

Page 4 of the Rules Reference:

• If the defender does not have unrouted units or bastions in the area at the start of a combat, the attacker immediately wins the combat. Players skip the preparation and execution steps and move directly to substep b) of the resolution step.

No dice are rolled; no cards are played. The attacker just wins the battle and takes control of the structure.

[Wh0isTh3D0ct0r 360]

...also, no reinforcement tokens are played, which would be a pointless waste, anyway, since they would be unnecessary. The attacker doesn't need them, and the defender wouldn't be allowed to add reinforcement tokens, anyway, because you can only add as many reinforcement tokens as the number of units you control in the combat.