The Calendar Overlays feature lets you create a combined view of your calendars by layering more calendars on top of the master calendar. This means that you can have separate Calendars with different Events, but you can combine your Calendars as Calendar Overlays and see all of your Events at once.
If you want to keep the master calendar blank and only serve as the base to view all of your overlaid calendars then there is a feature that you can turn on to prevent anything from being added to the master calendar. This feature will prevent Day Notes and Events from being added to the calendar from the Event Editor or by using drag-n-drop. When anyone tries to add anything while viewing your master calendar they will be prompted to choose another calendar to save the event to.
To stop anyone from adding anything to your master calendar follow the steps in the image below:
After this feature has been turned on you or anyone that you have given edit rights to will not see this calendar listed in the Event Editor when you try to save an event. You will need to choose an alternate calendar before saving.