I understand that they do this at Wacken and it's very good fun! I think it may be a good idea for BS...but where could it be put in the Assembly Rooms??
The Blind Guardian signing queue had a kareoke metal sing-along! it was lots of fun, with renditions of Mirror Mirror and many Manowar songs! Kinda died after people began to forget the words though, as neary everyone in that queue was drunk I think...