In the last episode of season 5 the bride (which we learn in this episode to be Susan) is wearing a thick veil to prevent the viewer from seeing who Mike is marrying. In this episode the same scene was re-shot and the veil was now instead sheer enough to reveal that Susan was the bride.
When Susan drops her shopping bag to run over to Katherine's house, it is obvious by the hollow sound it makes that the jug that fell out of the bag was empty.