I've often wondered when this tradition began. It's been happening (sanctioned) for at least four years now. Without a doubt, the best time of the entire school year is the couple of weeks between Thanksgiving and Christmas. Partially because we all know it's almost over, and partially because of the little morale boosters like the Christmas carol after Taps.
I remember my rat year, the first time they did it. We had just had our traditional "welcome back" sweat party, and hearing that Christmas carol did wonders for our morale. My roommate and I were just certain the bugler would receive a huge penalty, because we didn't realize it's a sanctioned activity.
This year there wasn't very much Christmas spirit in barracks though. In years past you'd see cadets standing in their doorways in nearly all the rooms, singing along and then either cheering or booing depending on how well the bugler played.
But this year there didn't seem to be so many people participating.
Normally it's just the bugler who plays Taps that plays a Christmas carol right after, but sometimes there will be a special performance, like this one. They also have a couple nights when the quartet plays.
My Third Class year (Fall '06), two buglers played Echo Taps right before the traditional duet trumpet rendition of "Feliz Navidad". That stands out in my memory as the best Christmas carol ever.