Even so... it was an old superstition–older than books, older than writing–and beliefs like that were heavy weights on the rubber sheet of human experience, tending to pull people into their orbit.
And Magrat had been married for three months. That ought to mean she was out of the first category. At least‑ Nanny twitched her train of thought on to a branch line–she probably was. Oh, surely. Young Verence had sent off for a helpful manual. It had pictures in it, and numbered parts. Nanny knew this because she had sneaked into the royal bedroom while visiting one day, and had spent an instructive ten minutes drawing moustaches and spectacles on some of the figures. Surely even Magrat and Verence could hardly fail to... No, they must have worked it out, even though Nanny had heard that Verence had been seen enquiring of people where he might buy a couple of false moustaches. It'd not be long before Magrat was eligible for the second category, even if they were both slow readers.
Of course, Granny Weatherwax made a great play of her independence and self‑reliance. But the point about that kind of stuff was that you needed someone around to be proudly independent and self‑reliant at. People who didn't need people needed people around to know that they were the kind of people who didn't need people.
It was like hermits‑ There was no point freezing your nadgers off on top of some mountain while communing with the Infinite unless you could rely on a lot of impressionable young women to come along occasionally and say 'Gosh' .