In fairness cuchulainn, re. the replies being returned, we're booking a wedding at the moment (oh the joy!) and it is really difficult when people don't reply to invites (or don't attend when they say they will). It costs money, remember, for each person who doesn't attend.
If we are talking about rudeness, btw, I think not attending when you have indicated that you will is the WORSE rudeness. If you don't want to go, then say so.