Cheap formal wear?

[DWFII]

While it is a costume, it isn't fancy dress (I.e., a masquerade costume chosen to suit the wearer's fancy).

Well said.

I might add that if I had an audience with the Chieftain...or even if I were just making a pilgrimage to castle MacSween...I might wear a well-done-conversion Argyll jacket if I did not have a PC, but I'd rather wear jeans and a windbreaker than a kilt with rolled down socks and athletic shoes.