Minato wouldn't remember either, but he did wonder if it had ever crossed her mind or bothered her, whenever she remembered.

"Probably not Wonderland itself. But we can find ways to back them up for you."

As he mentioned before, though he said it again also for his own benefit, just so he could think of ways to do that, make sure they stayed safe. In case someone decided to steal them or if there was an event that would destroy the notes, like a fire, flood, anything like that. Wonderland would keep her from being able to read or write certain words or phrases, but they'd be there for someone else to read for her.