I'm not a GPB but this is what we always did...the pledges came upstairs one by one and went into one of the upstairs bedrooms. Then her big knocked on the door, the pledge opened it and there was her big sister. They didn't sit together so none of the pledges following would figure out who the new big/little pairs were.
I can't figure out why any of these other things would be hazing, unless you're allergic to string.
