My husband wore his family plaid to our wedding and it's the one thing people who were there remember, five years later. Not the "Steel Magnolias" reception theme on which I worked so hard. Not the exquisite chicken piccatta. Not our hired DJ being stoned off his gourd and playing rap during the meal.
It worked well in combat with blades, but I don't think it works quite well in combat with guns. Plated pants would be more effective, I think, though adding a plated skirt to obfusicate the silhouette of the soldier may be effective as well.
I know this is a common misconception about the states, but I actually don't have to wear ballistic clothing unless I find myself in Los Angeles for some reason. I'm generally far more concerned with what the weather is doing.
I see kilts on the regular in the PNW. Not every day, but if I leave the house often enough usually a few a month. Plenty of stores specifically for those out here too.