I think of it like car shows...Wear what ya brung"
Here in Maine, at the burn's dinner you will see everything from t-shirts with kilts to the really fancy jackets. I would say 50% are wearing kilts and sweaters that match a color in the tartan.
What the Heck, it is a fun night and usually for a good reason. Just wear your kilt and that is the main thing.
God, you say women are bad with shoes and purses etc.... :0)