@HuffPostWedding @HuffingtonPost do you say something to guests who add uninvited guests to their response cards or let it be?

- Stephanie Johnson (@mommysminutes) July 28, 2014

Anna Post -- great-great-granddaughter of etiquette guru Emily Post and author of Emily Post's Wedding Etiquette -- is here to help us answer this week's question. Find out what she had to say below:

It's up to you. It's understandable to prefer to avoid confrontation and possible hurt feelings, and if you feel it's better to let sleeping dogs lie, that's okay. For most couples, an unexpected extra guest can be a costly addition, go over capacity limits for the venue or cause problems with other guests who weren't invited to bring to a date but might have liked to.

It might seem rude to say something to a guest who added an uninvited guest to their RSVP, but it's truly okay to speak up. After all, it was really inconsiderate of the guest to RSVP for someone who wasn't invited. The trick is in how you go about doing it. Phone calls are the way to go -- they are more personal, immediate (rather than waiting for an email reply), and allow for no mistakes in tone of voice.

The guests in question should have known exactly who was invited (and by omission, who wasn't), based on the name(s) listed on the inner envelope (or outer, if there was only one). But it's possible they didn't know this, so give them the benefit of the doubt, but obliquely. You might be right, but an argument about the finer points of etiquette will only make things worse. Instead, say, "Hi, Sarah. We're so glad you can come to the wedding [open with a positive]. I'm so sorry if there was a misunderstanding [don't get into whose that might have been, it won't be productive], but the invitation was only for you [nicer to focus on who is included than who isn't]. We hope you understand and can still come [again, return focus on what you would like]."

Don't ask the guest questions like, "Is that okay with you?" because that could open the whole thing up for debate. Your tone should be friendly but firm. The ball is now in your guest's court to decide whether or not to come.

There is one exception to this: If the guest is married or engaged and their partner wasn't invited, the mistake was actually yours, as married and engaged couples are a package deal when it comes to a wedding invitation, regardless of whether or not you know or like the other half. In this case, the guest should call to explain the oversight rather than simply adding the partner to the RSVP.

You can submit your wedding etiquette questions via Facebook or tweet them to us @HuffPostWedding with the hashtag #MannersMondays.