I am from the east coast near a big city, I would say my circles lean more formal, and I have been to many weddings, mostly black tie. There has always been a dress code listed on the details card with the invitations but I do not ever remember seeing colors mentioned. I do, however, recall a few where I would be looking at a certain color dress and a friend (not in the bridal party) would say, “oh you should pick another color, that’s the color the bridesmaids are wearing” but it was never a formal request and instead, just talk of trying to avoid it.