Social Dilemma-Guests Bring Kids to a "No Kids" Party-What Do You Do?

Today's social dilemma happened at a party I went to over the weekend.  It was a "Friendsgiving" kind of situation where a bunch of us were getting together to spend time and get into the holiday season.   My friends who were holding the party at their house were specific about no kids being invited.  It was an adult only party.  Our friend group ranges in age and there are some younger couples that have kids.    Anyway, so we all get together and about 45 minutes into the night, the doorbell rings, and it's a couple of our friends and they have their two kids with them.  The kids are 7 and 9.  Now I could see steam coming out of my friends ears.  Her whole thing for this party was that it was going to be adults only so we could laugh and talk about anything without censor.   People would be drinking etc.   And the game changes when kids are there.  The couple said their babysitter ditched at the last minute so they had to bring the kids cause they didn't want to miss the opportunity to see everyone. Now I didn't mind at all, but it wasn't my party.  As I said my friend who threw the party was furious.  Anyway, I played with the kids a bit and then their parents laid them in a bed with an ipad and they were both asleep soon enough.  It didn't wreck the party at all.   We all ended up having a great time.  But at the end of the night my friend who had the party still said to that couple, next time, no kids.   Personally I think I would have waited to say anything.  So I thought I'd ask you.  What would you do if you threw an adults only, no kids party but some of your buddies showed up with their kids?  Would you ask them to leave?  Would you let them stay?  Would you be furious with them?  Let me know on the TRY Facebook page.