When appointments are inserted from the Calendar it is possible to create them outside the schedule of the agenda. In case you want to be notified when you are going to insert appointments outside the schedules of the agendas, configure it from the Control Panel.
Go to My Center and under “Other Center Settings” check the last box: Notify me when trying to create a booking outside the schedule from the calendar.
Click on the save button for the changes to be made correctly.
This way, when you go to create an appointment out of schedule, a window will pop up notifying you of this.