On the Check-In/Check-out Event Records window, the final tab is called Notes.
There are two columns in which to type notes on this tab. The left side is General Notes which is a good place for administrator notes. General Notes appear on this window and can be included in the Custom Listing Report if you choose.
The right column is Notes to display during check-in. Anything you type in this column will appear for the staff member each time he or she checks in an individual to the event. It’s a good place to put reminders to the staff member who will be performing check-in.