Tzitzis

The following thought crossed my mind as I was editing my profile on Frumster:

Among Rishonim, the Rosh holds that tzitzis is required for any daytime garment, even at night, while the Rambam holds that tzitzis is required for any garment worn during the daytime (v'simanach: the German holds it's a din in the garment). Isn't it interesting that the minhag among ashkenazim is to only wear a beged d' kanfos or a tallis during the day?