Maybe she just gave your friend the bag as a gift. Who cares if there wasn't anything inside of it? Just because she's a witch doesn't mean that it implies something. I always make candles for my friends, and just because I make them black (which I usually do) doesn't mean that I want to put a hex on them. (Just to make a note here, I associate black with more than hexes, but hexes are one thing I associate black with. Black could mean something completly different to another witch, practicioner, etc.)
