Video: A Flash Mob in the U.S. Apple Store

A flash mob describes a brief, seemingly spontaneous crowd on public or semi-public places, in which the participants do not know personally and do extraordinary things. This is the explanation on Wikipedia.
Now it has caught an Apple Store.
Chris Brockhoff and Hayley Kiyoko, two of the stars from the Disney production Lemonade Mouth, organized the surprise appearance with about 15 of her friends