User blog comment:Silva-zoldyck/what if... they caught annie before transforming?/@comment-7418318-20130924083233/@comment-7418318-20130924111031

In her Human form it might not matter, but maybe for the transformation process itself.

The energy to "conjure" such a big form out of nowhere must come from somewhere. It is possible that the Human body has enough energy stored up for it, but maybe not.

Since depriving her of sunlight won't hurt the interrogation process, nothing's lost by trying. Covering up the windows is neither risky nor costly, so there's really no reason not to do it.