As far as I know, and for me personally, a sporran is not only a handy place to keep keys and to keep you're kilts down (depending on sporran weight) but its usually the thing that makes people stop before they say 'nice skirt' and say 'nice kilt' because they recognise the sporran as part of traditional dress.

If they still say its a skirt then there's not really much matter with that, though if you have a sporran it rarely happens. Please, don't tell me about how no-one has called it a skirt whilst you've worn it without a sporran, people are probably not as certain to say that where you come from as here (though I don't know, I'm just giving my opinion).

James