Whether because you have limited supplies, food, money, etc., apologizing to the bringer of extra guesta that, "Oh, I wish I had enough of . . . " is completely reasonable, emphasizes your desire to be a good hostess rather than an exclusionary one, and also points out that we ask people to RSVP for a reason! Adding, "I'd be happy to drive Susie home" is especially generous and suggests that you're serious, but that there are no hard feelings and you want to help.

Every family does things differently, so maybe the family with 4 extra siblings at the party is accustomed to doing family events where everyone and his/her brother is included. So while I'd be inclined to forgive their rudeness (uninvited guests are just rude, no matter what the cause), that doesn't mean I have to cough up the extra cash or ruin the activities of the birthday kids in order to cover for them.

Age is also a factor: when my daughter was turning three we expected that a parent would stay and so we also invited siblings. (Some parents turned us down, saying that it was nice for one kid to be able to do something on their own sometimes!) When she turned four, it was a kids-only party, as the rest of the parties have been since then. In that case, if the parent isn't staying I'm not sure why other siblings would need to.

Still, if you don't know the inviting family well enough to call them up and say, "I wasn't clear, was this invitation for everyone in the family or just little Jane" (despite little Jane's name being the only one on the envelope and card) then you don't know them well enough to be bringing kids who are not friends of the birthday kid.

When my daughter turned 5, one mom (who I didn't really know) called me and said, "I'll have my little one with me that afternoon. Would it be OK with you if she and I hung around and I could help out with the party?" That worked out fine -- it was at my house, but if it hadn't been we could have discussed that issue as well. And I suppose if there had been some really raucous activity planned I could have said, "Well, you might not want to. The girls will be using explosives, and we've gotten a sitter for our own littler one." Hopefully that would be enough of a hint!

Shaun
www.homeschoolblogger.com/shaunms