My neighbour who has a daughter in year 12 at our local public state high school (around 2000 kids) was telling me today that its fine to bring your boyfriend/girlfriend from outside school to the formal as your partner as long as they're under 20
But if her daughter wants to go to the formal with one of her girlfriends (doesn't have a boyfriend not overly fussed about getting a date) then they have to sign a form to say that they're not in a same sex relationship!!!!!
no idea if this applies to boys as well, or how it works if a group of girls or boys were to go together as a group to the formal or god forbid you were actually in a same sex relationship. But jeez it's 2013 and it's a state school!