[quote=Sightles]
She should be able to keep track of herself. A walking cane would be easy. Given she has just turned blind recently. I can have her manage by herself.
[/quote]
The housekeeper has to make sure each child follows the schedule. While she might be able to take care of herself the housekeeper needs to know where she is. If she and everything she touches goes invisible the housekeeper would lose track of her.