How does the "no opportunity fire vs. skirms" work exactly?

[jonnymacbrown]

I gamed this out a bit bit and I'd advise all Allied players to avoid the "no opportunity fire vs. skirms" rule. It applies to all units, arty and infantry. French skirms, especially the large ones, can walk right up to Prussian units in line formation and inflict HEAVY casualties without return fire. von ege