hahahaha.
In many ways, she's right though. In today's houses which are sealed and the fresh air is recirculated through HEPA filters in our HVAC's etc etc. Where do we think the wild yeast actually comes from when you are starting a culture. It's a combination of what you carry in from the outside and what you leave in the loo.
Something to ponder while you slather some butter on a slice of your loaf and enjoy every mouthful. Hrmmmmm.... I wonder where Brewer's yeast comes from?
You must have done fancy houses there, mine is a big draughty old bastard with wind blowing in from never ending gaps!!
But yeah, yeast is yeast in the end. I guess I will be making Boaby bread soon enough!! ;0)