Over the years I have found that most people assume RSVP means to respond only if you are attending. I'd like to take a moment to inform folks, that is not exactly true.
"Répondez s'il vous plaît", a French phrase that translates to "please respond" or "respond if you'd please". In Western and European culture, it is often considered rude to not reply to an RSVP request whether confirming attendance or declining.
I have seen, on rare occasion, invitations that ask invitees to RSVP only if they plan to attend. However, in 99% of the invitations I send or receive that is not the case.
On occasion I have discovered that people will wait to respond at all because they are uncertain if they are able to attend the event. I can understand this, especially if there is only a Yes or No response. However, if there is a Maybe option, perhaps its best to respond with that and then change your response accordingly when you have a more firm idea regarding your attendance.
In some cases, such as Meetup events, it is also an option to change your RSVP, as much as you like, prior to the event. If you were a Yes, but discover you are unable to attend, you can change to a No. However, this may be different with an event such as a wedding where the head count is very necessary as the bride and groom have to pay for each person. So to change your response at the last minute can be costly for them.
This can also be a problem if the event, such as on Meetup.com, has a limit to the total amount of attendees. Often this is due to the venue accommodations. When a person RSVPs with a Yes, but they aren't able to attend and doesn't change their response or notify the organizer of the change, this takes away that available seat for someone who would have been able to attend the event. I have heard many Meetup organizers who create these type of events (often at restaurants with limited seating) complain about this type of rude behavior. I don't blame the organizer for being upset.
Currently I have an event listed through Evite.com. An unfortunate issue with this web invitation service is that sometimes the sent invitation gets lost in the receivers spam filter. I'm not sure why this happens, but it does. So when individuals receive the invitation, but do not click on the invitation link I am never certain if they ever received the invitation. When they do click on the link I am able to see that they did receive the invite and looked at it. When this happens, but they still don't respond with a Yes or No I am less inclined to be concerned about it. I figure they know about the event, but just didn't care enough to respond. I feel less inclined to send further emails or make phone calls.
If they have not clicked on the link and looked at the Evite, my concern is that they never received the information at all and might have liked to have attended the event if they had known, so I go that extra mile to make sure they're aware.
So if you receive an invitation to an event with an RSVP request on it, please take the time to respond with something. :)
