I was idly flipping about the map today in an on-going scenario, looking at the "deep south" areas the Yankee invaders have not yet reached to see what their level of support was there and hence what information they are receiving about my troop movements, garrisons, etc. Imagine my surprise to discover that 100% of the population across the Carolina and Georgia low country, the black belt of Georgia, Alabama, the Mississippi Delta, etc. support the Rebels.
I imagine this must be some quirk of the engine. Obviously about 1/3 to 1/2 of the population of those regions did not support the CSA. And that part of the population was an important source of espionage for the Yankees. Now perhaps the purpose of this is to prevent the USA from getting information before its troops are in the region to receive it, and I can understand that. But I hope that when there are Yankee troops nearby to report to, the (mostly black) Unionist elements of the southern population will come out of hiding and USA support will rapidly rise in those areas. This will allow the USA some intelligence in those areas. I did notice, by the way, that the areas of the south where white Unionists were most active - the mountain regions of western North Carolina, eastern Tennessee, and northern Alabama - do report significant USA support in the game.