being Wiccan really doesn't mean much with 'ghost hunting' mind you Wiccans don't like harming other beings, and i believe spirits are one of them, unless in self defense, and even then some Wiccan's won't.
casting a circle, or giving out protection charms might be their use, but things like seeing the spirits, you don't have to be Wiccan, people of every faith have the ability to see them. if you mean fight spirits off, again, most Wiccans wouldn't go out of their way to attack a spirit for no reason. i have seen some show s on cable tv about paranormal investigators, mostly fakes, i've seen one or two where one of them was a 'Witch' or a 'Wiccan', but it's rare. normally they're Christians, not that religion determines your qualification.
so yea, if you ask me, while a Wiccan wouldn't hunt down spirits just because they can, a Wiccan would probably tag along for protection.