My sister is getting married this month, so it's great to learn form her experiences. She invited all of the first cousins on our dad's side of the family, even though we aren't really close. We went to our uncle's funeral yesterday, and all of their kids were talking about how excited they were about our weddings. My sister told me the first cousins RSVP'ed along with their kids' names! That's 14 extra people (mostly teenagers). We calculated about $950 extra dollars.
I know this isn't exactly unheard of, but it's stunning when people you thought you knew don't have enough sense to know who is and isn't invited. I don't even want to invite any of the adults now. They know my sister doesn't have a lot of money. She has good friends that she can't invite because she can't afford it. Now these people we don't really know are bringing all of their kids, and some are bringing dates!
My sister begged me not to say anything. She is going to put her foot down on the plus-ones, but not the second cousins. I won't say anything until after HER wedding.