Well I also have to say if someone WAS invited to the ceremony, and didn't attend, but showed up at the reception, that's rather rude barring anything they really truly couldnt get out of, such as work etc. Not everyone can get out of work but if you really tried and couldn't I could understand that. But if you WERE invited to the ceremony and just didn't go, that is rather rude. It just really depends on how the wedding is set up. Some invite to the whole event, many invite only family/very close friends to the ceremony and everyone else to the reception.