Jeez, really. I always have and always will wear nice slacks, or tailored shorts, and an appropriate shirt/sweater etc.
I just don't get the jeans on a golf course thing. I wear jeans often, but never to a golf course, fine restaurant, family get-together or any social event. Two of the four courses I regularly play now allow jeans, however it is still pretty rare to see people on the course in jeans. Occasionally I have seen men (young and old) in jeans, but am pleased to say I have yet to see a woman in jeans playing golf: thanks ladies.