Calendar Bookings - Restrict Same Day Bookings?

How to I set my calendar bookings to restrict same-day bookings?

I have a special event set up for 9 days of mall Santa photos.
When I leave my house in the morning, I want to be able to take a print out of the bookings for the day so my helpers have that list and can manage it in conjunction with walk-in traffic.
I don't want people to be able to book the day of as it is just too many things for my helpers to juggle. 

You would need to add an entry to your booking calendar that morning and set it for like 12 hours and check the option to Block out all available slots for this time. 

Ah! That is clever. Thank you!