Wedding etiquette has loosened up considerably. Still, the “I do’s” are too often preceded by “Oh, no, they didn’t!” We consulted two St. Louis etiquette experts, Maria Everding of the Etiquette Institute and Melenie Broyles of Etiquette St. Louis, to help couples and guests avoid the worst wedding faux pas.

1. The wedding is not an opportunity to shake down your guests for cash.Under no circumstances is it proper to indicate that you prefer cash on your wedding invitation. Euphemisms such as “No boxed gifts” are just as rude. Everding said she has seen couples’ websites that ask guests to sponsor dinners and activities on the honeymoon as a gift — complete with a list of restaurants where they will be vacationing. Tacky, tacky, tacky! A registry card may be included in a bridal shower invitation but not in the wedding invite. Rely on word-of-mouth to spread where you are registered.

2. If the invitation is addressed to Mr. and Mrs., your children are not invited. Do not show up with them or send a response card with your brood included. If the bride has invited out-of-town guests who are traveling with young children, it is gracious for the bride to make arrangements for the children during the reception, such as a designated child area with a sitter. An “adults-only” line can be included on the response card.

3. RSVP does not mean you only respond if you can’t make it. It does not mean that you assume the bride knows you are coming. It should be mailed back promptly — preferably long before the date indicated on the card. If the bride has not heard back by the date, her mother or bridesmaid needs to start calling those who have not responded.

4. Thank you notes should be written and mailed promptly. Broyles says any wedding gift received before the wedding should be acknowledged with a thank-you note before the wedding. Guests want to know if the gift they have purchased actually made it to your residence. For the remaining gifts, you should write thank-you notes every night after your honeymoon until they are done. The note should specifically mention the gift. And, the husband can write thank-you notes, too.

5. Discuss who will pay for what in advance. This prevents misunderstandings and confusion among family members.

6. Consider the financial impact of your wedding on your wedding party. There is the cost of bridesmaid dresses, travel costs, shower expenses and the gift. That can add up to a small fortune. And, do not invite the same people to multiple showers and expect multiple gifts.

7. Even if you are moved by the spirit of altruism, do not force your guests to contribute to a charity you have chosen in lieu of gifts. It is acceptable, however, to politely indicate: No gifts, please. Guests should honor this request.

8. As a guest, do not move place cards or rearrange the seating chart.

9. Do not embarrass the bride or groom with inappropriate comments during a toast. If need be, the couple should appoint someone with the power of the hook.

10. Do not fixate on trying to have everything “perfect.” Be flexible, roll with the punches and behave with poise.