To prevent your event from being viewable by the public, follow these instructions.

If you have an event that, for some reason, you have previously published and wish to un-publish, here's what you need to do. 

Log in to your promoter account, and find the event in question (within the events tab). Click its menu button, then "Edit". 

Once in the event edit interface, advance and save each page until you reach the "Review" page. 

At the bottom of the "Review" page, select "Unpublish Event":