My husband would have a heart attack if I tried to wear a thong in public. Not that I would ever feel comfortable doing it (I don't even like thongs as underwear, much less outerwear!). But he always comments on my cleavage when he thinks I'm showing too much. I don't really understand it, but I generally respect his wishes, especially since they coincide with mine usually... I'm usually covered neck to knees.
Not that I'm particularly conservative, I just feel more comfortable when I'm covered. It's like someone else said... I give off the suggestion of having a body, without actually proving it to anyone.
It could have something to do with the fact that I work in a law firm so my idea of "appropriate" attire is conservatively skewed.