I personally think that the playback talk should stop...it's wishful thinking though.
As I and others have said, it's better to be blissfully unaware and be able to enjoy a concert, and then come to your own conclusions, but it just gets irritating when members of this forum continuously try to persuade everyone else to believe something is playback.
Like, I think it was, TH said, we're never going to know whether or not a song is playback unless Ayu messes up with the lip movements. Other than that, no matter how strongly your intuition says, it's purely speculation.
I don't see what's to gain by pointing out playback and then trying to get everyone else to agree.
[/my involvement]