The lighter weight tartans are "flippier", instead of "swishier" when someone is walking.
I hate to disagree, but I do plenty of walking in my kilt and I can personally vouch for the swish factor. In fact, I feel more 'feminine' wearing my kilt feeling the swish as I walk, than I do in most other skirts in my wardrobe. And, while the length of the fell certainly is a major contributing factor, the fact that my kilt has 29 pleats, 3" deep, makes even the light-weight of the fabric heavy enough to make it swish.

Hmmm. I guess only a video with me walking away from the camera will settle this?

(I keed, I keeed)