Regular townies turning into spellcasters?

I don't mind occult showing up in the real world from time to time, alien abductions and vampire breakins. However, I don't want my existing townies and premades becomming spellcasters. It's the same with situational outfits. I make all of my townies, and I don't want to see their personalities ruined by them using magic or dressing in a wrestling mask. The game should spawn new spellcasters just like every other occult. They wouldn't get away with randomly turning pre-mades into vampires, so why is it okay with witches?