Board Thread:Speculation House/@comment-27883360-20160305074527/@comment-24772070-20170120232634

Ember Celica wrote: Idk, there might be people with passive semblances. I wouldn't doubt it. Yeah, Yang and Nora and Qrow all have passive Semblances.

Sure, Yang & Nora may actively use their Semblances once they've been activated, but Nora is (presumably) able to draw power from electricity at any time, even if she's taken by surprise. I expect the same thing is true for Yang.