Per your support I got this:
“If a cleaner is marked unavailable for a date then the system will not send notification for new booking but they can see the booking in an unassigned folder and can grab it from there. System sends the new unassigned booking notification to available providers only.”
However, often cleaners will want to pick up extra work even when not available. There need to be an option for Unavailable cleaners to still get notifications for unassigned bookings and to have access to the folder.