Dear DUmmies--the only reason I had yesterday off (with pay, I might add) is that the NRC rules set forth dictated that I have that day off due to working 72 hours in the previous six days, and would have been in violation had I not been given a day off.
Oh, and NO company I've worked for since I left the Navy has offered it as a matter of course. When I worked for SCE it was an "optional" floating holiday, along with Good Friday, Cesar Chavez, and Columbus Day, IIRC.