Who Do You Invite?

Recently, we celebrated my youngest daughter's 10th birthday. I rubbed my hands together eagerly, picturing the explosion of decorations, games, etc. that - let's face it - are my raison d'être. Imagine my (mock) horror when she announced she wanted her party at The Art Studios (formerly Luci's Mudhouse). "But HONEY" I pleaded. "This is what I DO!" (She will not be appearing in any upcoming endorsements for Hullabaloo.)

She actually knew exactly what she wanted: the party would start at The Art Studios and then work its way back to our house where (joy oh joy) I would be able to plan and decorate to my heart's content.But here was the kicker: she was only inviting a few people from her class and excluding any friend, no matter how close, who was not in her class. "But HONEY" I pleaded. "What about little Matt? He'll be heartbroken!"

"He's not in my class. I'm only inviting people in my class" she reasoned."But what about that time when the two of you were at Lucy's Mudhouse and you said your friendiversary was coming up and you should pick a piece you could do together and little Matt said 'yup'?"She was unwavering and the party went on without little Matt. (Before you reach for your kleenex, apparently little Matt was unfazed and is using the same principle, as are her other friends.)

Long story short, there is an understanding in her "group" that you only invite friends in your class to your party. This was new to me. Is it commonplace now, in your experience, or perhaps an anomoly?