I wear modern gaiters while hiking or snowshoeing, for the utilitarian reason of keeping junk out of my shoes. When it's cold out I wear tall, knee-high gaiters, and when it's warm I wear ankle-high gaiters (which are like spats). I'd never wear them any time other than when I'm adventuring outdoors. They're certainly not part of a "costume" but then I never wear my kilt as a costume.

Andrew.