[isthisLOL?]

No, it was on the TV broadcast, the camera was right on her mouth when she lipped the wrong word. It happened for theme of a-nation at CDL0506, too.
And it's not the first time Ayumi lipped, she used to do it in almost every concert for a few songs(hell she even used the same playback for evolution MANY times), she stopped after AT09 as far as I know. Most of her fans think she is perfection and deny it though, but I can fully understand why she would lip a few songs every now and then considering her ear-situation so I dont think it should be as much of a taboo as it is.
PCDL is probably the concert with most playback, noone is sure how much exactly but probably around half of the concert.