In the past, the East Village holiday tradition known as Unsilent Night has proceeded undeterred against the red menace that is SantaCon (remember UnsilentaCon?), so it’s surprising that something would stop it in its tracks on its 25th anniversary. But this is a brave new world we live in, and the annual roving sound collage orchestrated by composer Phil Kline has announced that it has moved the date of this year’s stroll “due to a large political rally in Washington Square Park planned for the same evening.”