I don’t have time to ponder Potter’s wardrobe choices. The best man (me) is responsible for ushering guests into the adjacent hall and strictly enforcing the seating chart. I have exactly seventeen fortes, and bossing around overdressed people is one of them. The key is comporting oneself in such a way as to remind them that they are playing dress-up, and you are not. I wear the suit, the suit does not wear me.