When you create a booking page the default is to show the availability to visitors of the page. This is great as it shows the visitor when an event or venue is busy.
Sometimes however you may not want the public to know either the capacity or the availability. Some reasons for this include:
You want to the availability private
Displaying this information isn't helpful to the visitor
Hiding availability doesn't disable availability caps
Even when you hide the availability full slots will still appear greyed out to the visitor indicating a time slot is full