I don't know, but something tells me that the kids' party was all set up, I mean, what would they do if those children didn't yell that way? What if they didn't even care who Katy is like "so what, we don't give a damn about you?" it would be pretty embarassing and I honestly don't think that children at their age (around 5-7) listen to any kind of music.
I think they choose the kids' party because it would have been less obvious that the whole thing was set up, like who at their 80s go crazy around Katy or at a Bar Mitzvah full of adults and relatives... Anyway, the video still nice
PS:
Worldwide sales: @katyperry, PRISM 37,000 (
2,785,000 total).
Pretty good numbers, it will easily cross 3M during her PRISMATIC TOUR ^^