It only works, however, after they get so used to it that they automatically assume that ALL little girls are villains.
Ugh. My players are so jaded; I had them run into a cute little girl once, and they almost violated causality trying to kill her. Appearently my concept of "adorable" is the same as their concept of "creepy and obviously evil."
In all fairness, when they had met her in the future she was a villain, but they didn't know that then.