It's still good to be there. There may not be any logical reason to stay there, but it would probably get you brownie points if you went when your girl asked you. Maybe she plans to ditch the guy she's paired with and sneak in a dance or two with you? It's probably a good idea to go anyway.... even if you're alone most of it, it's still you who gets to take your Girlfriend home, so being there is a good choice. :-p