[guyzero]

What possible penalty could one city impose on another?

[matte_black]

Imagine a future where cities go to war with each other to win the favor of massive corporations.

[rlanday]

More relevant to the topic under discussion would be a future where cities go to war to keep each other from winning the favor of massive corporations.

[internetman55]

Its lit!

[tzahola]

Revival of medieval city-state wars!

[bryanlarsen]

Any sort of collusion agreement can have a penalty clause, so presumably punitive damages.

And damages to reputation are also possible.