Apologise for what? They weren't listed as being there, so it's not his fault that a rumour starts up. Really it's Warner Bros who should apologise. They had 12 months in which to organise this better. Seeing the quanity and quality of stars who did attend, do you think they were asked a week or so before turning up? I think not. WBs would know how important this conference is more so than the Potter cast. In the UK we have nothing that compares to this. So blame WB.