In S. Austin it never really got cold, just a couple of degrees below freezing. The roads were always passable, although bridges eventually iced over. Thus, there was a lot of heat in the ground, and there was no wind to suck warmth out of greens, so perhaps covers weren't needed.
On the other hand, my local course, Grey Rock, is preparing to shut for spring and summer to completely rip out and replace greens and tee boxes, so I suspect they weren't too worried about it regardless. In any event, they have announced they are closed at least until Wednesday due to massive amounts of tree damage.