Well if she did go out for that "ritual" thing, she may have gotten mobbed or something. At the airport there may have been like 1000 people but at her concert there were around 10 000... They'd need extra security to keep all those people contained..
Maybe too Ayu didn't want to be "revealed" until the official opening of the concert.. Maybe she didn't wanna spoil the mood ;P She also could have been busy getting her hair+makeup ready
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