I wouldn't second guess the captain as well. I am making an assumption that you left from Ontario rather then LAX. Frost on the wings would make more sense in Ontario. As to having de-icing equipment...it would probably sit around unused. I haven't seen too many ice or snow storms in that area.
My wife and I are travelling to Ontario this month on...EGADS...Continental (already booked the flight a couple of months ago...before the latest fiasco), but we are arriving three days in advance of the cruise. We have family/friends there and can visit them. Plus...we won't be taking a chance on a delay.