LOL can you come stand guard for me that day & do the deed?!?!?
It is easy, all you say to anyone who shows up with a child is ". It was so nice of you to stop by to wish my parents a happy anniversary, it is a shame you couldn't find a sitter and can't stay for the party but it was a nice gesture to stop by and wish them well in person"
I don't get these posts giving the op advice on contingency plans. She has 185 people comming to her house and children aren't invited so she should not have to deal with a contingency plan for kids that aren't invited.