OK, I'm going to let you all in on a little secret about etiquette; specifically about response cards for weddings:

1. If you are or aren't going to be at the wedding, send back the response card.
2. If you are a member of the family, and are expected to be at the wedding, send back the response card
3. If you have talked to the bride or groom via e-mail or telephone after receiving the invitation, send back the response card.
4. If you are looking at your invitation and you notice a smaller envelope with postage on it, send back the response card.

This public service announcement is brought to you by frustrated brides and grooms everywhere, who remind you: please return your response card!