The bride does know when the groom will show up. . .the date has been planned and invitations sent out. But weddings here do still preserve the tradition of the groom coming to the bride's home before the wedding and, with celebration and fanfare, taking her to the wedding feast.
American weddings are beautiful. We incorporate a lot of symbolism into the ceremony such as rings and unity candles. But we miss out on this one aspect of illustrating that the Church isn't getting to Heaven on her own. Christ is coming to claim his bride and take her to the wedding feast.