So there I was in a late mid-game playing Korea and wanting to make some tanks. Only one issue, I had no oil. Was able to grab 100 barrels from Nubia for 1000g and then make them. Turns continue and suddenly I'm low on oil. I try to buy more and now Nubia wants nearly 8000g for 10 barrels while everyone else only has a barrel or two they won't sell. Great, I think, those units are toast. But it never happens. I get Low Oil warnings every turn and yet the tanks don't lose any strength, I don't lose any of them after several turns, and now I'm confused. What actually happens when you get low resource warnings for units (tanks, armor, artillery, etc.) that need resources per turn? Right now it looks to me that you definitely need the resources to make the units, but after that nothing happens. The resources are consumed if you have them but lack of them doesn't affect the units.