For U.S. Government employees, National Tartan Day is already listed as a special day on the Diversity Calender.. There hould be no problem, especially if you are of Scottish heritage. My organization already featured me on one of the diversity newsletters, and folks are already expecting me to be kilted on National Tartan Day. Once I break the ice this year (I'm new to the kilted world) I'll probably wear a kilt to the office from time to time - for example, on July 1st to celebrate the repeal of the Acts of Proscription.