User blog comment:ChishioKunrin/Monty's AMA answers/@comment-122.107.156.81-20131110071428/@comment-3146930-20131110072704

Except Sun came from some other country and Penny probably isn't a student at Beacon (or any school) if her caretaker won't even let her walk around the city; so Velvet, Sun, and Penny wouldn't be on the same team.