As a female, who is rather involved in fashion, I do not find polos good-looking on men. To me, it makes them look prissy & too feminine. I like my men masculine, not feminine. I don't really care about the price of clothes men wear, as long as they look presentable & good & clean. I kind of like the "punk" look on men.
I think this really depends on the type of girls you are dealing with.
I wasn't aware of this phenomenon, personally... If you mean Ralph Lauren Polo, girls might find it attractive because it's a fairly high end brand that looks nice... otherwise, it probably just depends on the individual girl's taste.