I suspect Cas would find the idea of a fangirl army completely reasonable. (And not just because Misha is... well, himself.) After all, prophets and heroes are supposed to have followers. Through the desert or on Twitter - times and circumstances may change, but the principle is pretty similar!

Btw, Becky was played by Emily Perkins of the cult Canadian horror Ginger Snaps (and sequels). She is AWESOME.