Maybe you've decided that you want adults only at your wedding...
This can be a sticky subject, but once the bride and groom have made a decision, everyone should respect it.
If this is you, start by carefully addressing the invitation. Consider writing, "Mr. & Mrs. Jones," and then pre-mark the response card with the number of guests, two, and they can mark "will attend" or "will not attend."
It's not proper etiquette to write "no kids allowed" or "adults only" on the invitation. However, If you need verbiage on the response card, you could say "Regrettably, children are not able to attend."
While it can seem really difficult to exclude anyone, it is perfectly fine to only invite children who are a part of the bride's or the groom's family, or those of close friends.
If you are the guest...
Do not make a big deal out of this! Only the bride and groom know what they can afford as well as what they want. Please, be a good friend and respect that.
Happy Wedding Planning!
Photographer: Rob + Deanna Photography