I saw a short clip of backstage of HM on doombuggies.com and I think it shows how the ballroom is done. From the looks of it all the "happy haunts" are above and below the doom buggies (which is why are are so high) the ones on the table are below and the ones in the air are above (like that wasnt obvious but eh..) My theory of it (since the clip didnt show much) is that that room is actually empty and we are seeing the "reflection" of the AAs through the glass. But I still don't get how they look so see through but hey I don't know if that is even how it's done, if anyone has any information on it, PLEASE share