Store Pickup + Delivery Blackout dates are real easy to get your head around. They are used to disable pickups on specific days of the year. To create a new Blackout Date with Zapiet, simply edit/create a location and click the Blackouts tab at the top of the screen. Then click the Add blackout date button and enter the date you wish to blackout.
You will notice that there are two checkboxes to the right of the date field. These allow you to specify whether the blackout date applies to just pickups, deliveries or both.