Not unless they're still in the (broom)closet. Oh, wait Tery might qualify as being wiccan but there is a difference between being a witch (white or otherwise) and being wiccan, you know.
Indeed there is. The description Dio posted is a good explanation. While I am a Wiccan, I also consider myself a Witch. I would add that Wicca tends towards organization, which is quite a feat. You've heard of herding cats?