You know what's rude? Making friends and family sit through a boring hour-long ceremony where two people talk intimately about their feelings for each other, before they can drink a beer. That's rude.
We kid, we kid. Wedding ceremonies are not just some useless obstacle in the way of an open bar and buttercream frosting, after all. The ceremony is the setting where actual vows are spoken and — if you're lucky — where some of America's funniest home videos have been recorded. It may not be exciting for the guests, in other words, but most grown-ups have come to the realization that others' weddings are not entirely designed to cater to them.
Is there ever a time to skip the ceremony and just go the reception? Sure! If you're not invited to the ceremony [source: Miss Manners]. That's really the meat of the issue; a formal invitation is not a choose-your-own-adventure arrangement. Some would argue that distance or timing might make a trip to the reception alone easier than a trip to the ceremony too, but these are decisions you have to make, confirm and stick to well before the event. Not sure if you can make it in time for the ceremony? Either tell the bride and groom the issue, and ask for a dispensation (and be ready for them to not give you one), or just suck it up, and say you can't go.
This brings us to the RSVP. You better believe that if you confirmed you would be attending the ceremony and reception, it would be incredibly rude if you didn't show up. Of course there are sudden illnesses, family emergencies or even unbeatable traffic. Sure, life happens, and if you are forced to cancel or arrive late to a wedding reception, so be it. But simply wanting to avoid the candle-lighting ceremony or the umpteenth listen to Pachelbel's "Canon in D" is no excuse.
Some people want to avoid the ceremony because they have an uncomfortable past relationship with one of the participants or simply don't know the couple well [source: Bodgas]. Let me just happily go out on a limb here and say "get over it." If you don't want to go to the wedding, don't just try to show up for the free champagne. If you do want to go, accept the fact that it's an event on the host's terms, not yours. An invitation, after all, is not an obligation.
In short? It's not about you, dear. Let the nice people have the wedding they want, and suck it up to attend the ceremony if you can. It will give you ample opportunity to practice another common wedding custom: gossiping about things you didn't like behind the couple's back. Mazel tov to all.