stealth_nsk
Deity
I think city re-capturing happened not too infrequently in Civ5, actually. If your army was approaching from one side, and other army was occupying a number of tiles behind the city on the other side, then sending a single weakened unit into a city, which, having just been captured, would have very low defence, was often a recipe for immediate recapture. The halving of the population each time wore down the city quite rapidly, but at least there was the opportunity to retake something.
Maybe, but not too often too. Also, in Civ6:
- Conquered city instantly regenerates 50% of Health.
- Due to blockade mechanics it's more common to capture cities from all sides.
- A lot of Warmonger penalties for razing a city.
So I expect this to be even rarer case.