Well this is actually really simple for me as well - I don't wear make up at all. The only time I ever wear make-up is if I am attending a wedding or a ceremony of some kind... and even then it is just the basics... I don't tend to get all decked out. I find that make-up when applied appropriately looks good on most women, but it really isn't a needed thing... more of a preference in my opinion (unless you are really that self-conscious/ugly that you feel the need to wear make-up - although I think everyone is beautiful without it).
I also think that it is impractical to wear make-up out in the bush, or when you are camping deep in the woods. What's the point? I mean if you are going to be hiking, building campfires, swimming, portaging, canoeing, and sitting around a campfire... then is there really a need for make-up? In my opinion, no.
The only time that I could see women wearing make-up whilst outdoors camping is if they are at a big commercial camp ground where they hold dinners and have golf clubs... then.. I could see why some women would choose to bring along make-up and nicer clothing.