This is a practice I have never heard of, but I recently read something by a TV critic where he compared something in fiction to the "southern men of supposed civility watching men die from the hilltop in their lawn chairs and lemonade".
I suppose he could have been talking about generals, but the idea I get from the text is that southern civilian elites, upon hearing of a battle likely to occur near them, would assemble at whatever distance they deemed safe to observe the fighting armies amidst a generally festive atmosphere (hence lemonade and lawn chairs) while rooting for their side to win, not unlike a sporting event.
Is there any documented instance of such practices during the civil war, or is what I have described a purely fictional/anecdotal notion?
The most famous case, and nearly the only well publicized case, of civilian spectators is at the very first battle of the Civil War, First Manasas (aka Bull Run). Moreover it's most famous for Washingtonians, in other words northerners or Union supporters, coming out a few miles from the city to watch the affair.
The motivation is wrongly depicted also, the spectators at Manasas didn't know how terrible the war would be, but they would soon learn. Both North and South initially expected that the war would be a brief and somewhat bloodless affair, the North expected an easy victory because the Southern forces were disorganized, and Southerners expected the Northern forces to crumple due to lack a military tradition or fighting spirit. It was extremely shocking to both sides that battles could involve 10,000 casualties in an afternoon and the war would drag on for years. After Shiloh in 1862 in particular, most civilians became very much aware that battles would be very bloody and dangerous affairs, in no way safe to watch. If this had been realized before the war, perhaps their would not have been one.
Lastly, while both Northern and Southern elites were callous at times, they participated in the war as officers at a high rate and would have seen high casualties amongst their friends and relations. The war was not really seen as a picnic after 1861 even for the elite.