The sweaterkilt is also a feature of contradancing, in that it instantly changes the sex of the person wearing it (for dancing purposes). Let me explain.
Contradancing is done in (multiples of) two long lines, one of men and one of women, evenly matched into partners, who alternate dancing with their partner and successive members of the opposite line. Let's say that there's a dance going on and a few singletons show up: usually no problem, because people are usually switching partners every dance, and a few sit out and clap anyway. But maybe you'll get a lot more men than women or (it could happen) women than men. Big problem. Unless...
I've often thought, since the contras are a way to get all the interested parties of a village in each others' arms, at least for a few moments, whether this, or some similar ruse (I've heard of armbands used to the same effect) wasn't used by some gay men (and women, too) to secretly gain a little time in the arms of their loves...